Scarterra does not have trained ravens that can fly to a pre-trained location to fly to while carrying messages (though tengku are often good at sending messages and they vaguely resemble ravens). There is not a lot of magic that can carry messages, the closest thing Scarterra has is magic spells that make someone better at traveling. The main, if not only way to get a message to someone not in earshot is to give a message to a person and ask them to carry the message to another person. In a noble's househould, messages are delegated with servants all the time. Even among commoners every member of the family will get drafted into messenger duty at some point. "Go tell your father that dinner is ready." If you have a trusted friend or family or servant or minion, sending a message is easy, but sending messages are unsurprisingly harder to send the farther a message needs to travel. Typically, if a person needs a message delivered and they don't have a friend, family member, or minion to physically send to the distant location, the only option is to ask around "who is going to insert name of a foreign place here?" and give them the message. Because they both travel a lot, there is a lot of overlap between Scarterran merchants and Scarterran messengers. Even a merchant can't or won't act as a messenger, most merchants keep track of who is going where, so if you want to find someone who can carry a message for you, there is a good chance they can point you to someone sufficient.
Casual messagesUsually a traveler acting as a messenger is traveling for some unrelated reason and will deliver the message, eventually. In most cases messengers carry messages as a side-hustle to whatever their main job is. For instance, a traveling circuit priest could carry mundane and secular messages with him in his travels. Likewise traveling performers often carry messages as a side hustle. Most of the time, if a cargo ship is moving bulk freight by ship across the sea, the ship in question will usually also be carrying messages to the next port. If a noble lord or lady needs to send an official message to another lord or lady, and the message is not urgent or time sensitive, the servant of the noble household will probably take up a couple other people's messages on the trip. Then there are messengers that are nothing but messengers. This is typically called an "expedited message." With an expeditated message, the person will take the message or messages directly to their point of delivery and (at least in theory) not treat the journey primarily as a means of dealing with personal business.
Expedited messagesHiring an expedited message is never cheap, at least not to common folk though this is something nobles and very successful merchants and adventurers can be able to afford. Hiring an expedited message is not guaranteed. A messenger that fails, or worse, betrays the person paying them for taking a message to a new location is going to suffer a great loss of reputation but in a lot of cases, the would-be messenger is too far away to need fear reprisals. Many secular and religious leaders understand that if the message is really important, it is safer to send a trusted retainer instead of hire a professional messenger.
While rare, some exceptional people have managed to tame flying mounts such as Pegasi. These people make great messages, but in many cases they are too proud to carry messages for just anyone. There are also intelligent flying creatures. Dragons rarely consent to acting as menial messages, especially to non-dragons. Kalazotz are not commonly welcomed in the wider world above ground, but as the bat folk are becoming more accepted, a great many are carving out a niche for themselves as professional messengers. There are also spells that can help defend a messenger from being read by the wrong person (such as with Smearing Scroll Cases though magical anti-espionage spells can backfire as a letter or scroll with a magical aura will attract attention by those who are mystically sensitive whereas an ordinary messenger will not.
Scarterra is a world of magic and while especially powerful magic is not especially common, it does exist. A messenger mage capable of casting overland from the School of Transmutation can move a message very fast but they are going to charge a lot, and they might not take mere coins. Shapechangers be they arcane, divine, or supernatural can turn into winged creatures and fly messages that way. Beyond flight, there a huge variety of creative uses of magic that can make travel easier, making messengers with almost any magic highly valued.
Messengers need to be willing and able. Some view it as a requirement for a messenger to be literate because this helps the messenger progress further and pass the message on to another messenger if necessary but other Scarterrans believe illiterate messengers are preferable because they have no ability or incentive to read documents given to them.
Messengers work by the job. Generally there is not much room for career progression, but in some rare cases a messenger that establishes a reputation for sending messages to distant locales safely can charge more for his services.
Payment & Reimbursement
Some travelers will carry a message for free as a courtesy, others ask for coin or favors. It depends on much of an inconvenience it is and how much they like the person giving them the message. A couple silver pieces is customary whereas ten silver pieces denotes a sense of importance, generosity, or minor urgency. It it is customary but not required for the recipient of a long distance message to provide a monetary tip or to offer them room and board for the night, but most payment comes up front. Direct messengers, who are expected to drop everything they are doing and deliver their message to the recipient as soon as possible, need to be paid a lot depending on how far and how dangerous the route is. Moving an expeditied message from northern Fumaya to souther Fumaya costs about 5 gold pieces whereas crossing an equivalent distance in the Border Baronies Region can cost 20 gold pieces or more.
Sometimes, if a message is very important, a messenger can swap tired horses for fresh horses at periodic intervals. This is generally only available for very high ranking individuals such as kings or dukes within the borders of their own nation. Swapping for fresh steeds internationally is generally not feasible.
Mounted messengers such as humans riding horses or gnomes riding reindeer can certainly cover ground faster than messengers on foot, and most expedited messengers worth their pay have a steed of some kind.
Dangers & Hazards
Messengers carrying sensitive information risk being robbed or even killed by enemy espionage agents. Even if the messenger is only carrying warm birthday wishes or something else benign, messengers can easily run afoul of the same road hazards that any other traveler faces.
gnomes and tengku acting as messengersGnomes and tengku do not look or act similar to each other but they are similar in that both lack a true homeland to speak of and normally exist as minority enclaves in the lands of other races. Also, both gnomes and tengku are generally highly literate and are overrepresented among the merchant and entertainer professions, so they are already tight with professions that commonly travel and carry messages. Both gnomes and tengku have set an informal communciations network to keep in touch with their kin over long distances. Gnomes are famous for being good at getting messages sent across great distances relatively cheaply. They rely on Order of Delas to do this and the Order relies mostly on goodwill between gnomes of distant lands, but non-gnomes can pass messages along this network if they have gnome friends and/or drop them some coin. Tengku have complex trading networks where messages are carried along with normal freight and trade goods and can efficiently move messages from one cargo carrier to another to hopscotch very long distances. Even among other tengku, tengku require coin to make sure the messages keep flowing, and they won't say no to non-tengku giving them money to use their messenger network though it is widely suspected that the bird folk will read your message before the recipient does so this is not ideal for sending senstive or clandestine messages.
"As if gnomes never eavesdropped on someone else's message... -Ecknok The tengku merchantIn both cases, accessing the gnomes' or tengkus' communication network is somewhere between a casual messenger (which is relatively slow and relatively cheap) and an expedited messenger (which is fast and very expensive). In other words, they are moderately fast and moderately expensive for carrying messages.
couriers, letter carriers
Messengers perform a fully legal service. Now the people sending the messages may be breaking the law and messengers can get wrapped up in this, but usually law enforcement won't kill the messenger in these cases, usually.
Other Associated professions