1. Press ⊞ Win + R
on your keyboard.
2. In the run box, type %AppData%
3. Navigate to .minecraft\saves\
4. Locate the folder with the name of your world.
1. Click the three vertical dots next to the play button on the modpack you've been playing on this world with
2. Open the saves
folder and your world folders can be found inside.
1. Open the File Manager
2. Drag the world's folder into the file manager.
*Note: If the world folder is large it's faster to zip it to avoid the upload hanging.
3. Change the World Name in the World Settings to match the world folder name
5. Restart the server and the save will load onto the server.