Datapacks
Datapacks are purely server sided, a server own needs only add it to their server's datapacks folder and every player
will use it. A datapack cannot affect client specific aspects such as item/block models, translations or textures.
This is not a full featured datapacks tutorial and basic datapack knowledge, such as file, pack or id formats, are assumed. These docs are meant to serve as a helping hand for datapack devs and what capabilities they can make use of when creating datapacks for Mine Mine no Mi.
Since Mine Mine no Mi uses a fair chunk of datapack features added by the base game (such as tags or loot tables) you can also read the Minecraft Wiki's page about datapacks for more info on how they work.
Minecraft Wiki also has a wonderful and easy to follow tutorial on how to setup and build a datapack which you can find here. With the very important mention that Minecraft 1.16.5 has a pack_format of 6.