Sending is a 3rd-level evocation with unlimited range, so if magic is common in your world, it might make sense for remote communication to take place via Sending. Maybe wizards provide Sending services for wealthy clients, or maybe one could have a lucrative business making scrolls of Sending.
Xanathar's Guide to Everything includes a rule for scribing scrolls. Crafting a scroll of Sending takes 1 workweek, 500 gp, a short piece of fine copper wire, and requires proficiency in Arcana. So RAW it's 20 gp per word. This means of communication would be reserved for the wealthy and powerful.
This seems to indicate that magical communication would be reserved for matters where a lot is at stake.
That said, the spell says that it can transport 25 words. But it doesn't specify a language, and it doesn't say how many bits of information could constitute a word. So without breaking the rules of the game, you could transport potentially very complicated instructions or entire treatises if you had a large enough vocabulary of sufficiently meaningful words. Perhaps wizards in your world could have come up with a language for communicating via Sending with extraordinary efficiency.