Installation and uninstallation
You can add one or more data packages to each world and change the data of this world. Step by step:

A new data package can be downloaded as a zip file from the Internet or compiled as an unzip folder itself.
In the menu / single player, a world is selected (not entered) and the "Edit" button is pressed.
In the Edit menu, the "Open Folder" button is pressed. This opens the world folder of this world.
Double-clicking on the folder datapacks opens the data package folder.
The new data packet (zipped or unzipped) is moved to this folder.
Upon entering the world, all data packets are loaded.
Later they can also be loaded with the command / reload.
The / datapack list command lists all data packets.
Use the / datapack enable command to specify the order of the data packets.
With the command / datapack disable a data packet can be permanently deactivated.
Also server worlds have a folder datapacks in their world folder (the world folder is set in the server.properties).

The standard world data is also a data package called vanilla.