Did you want to change a vanilla structure that you didn't like or create an add-on for another mod where you changed features? Well this wiki page will help you to succeed in your intent
Before starting
Be sure that the structure you want to replace has multiple files due to variation/size. In this case, simply add a folder named as the structure during the tutorial and put it into your .nbt files with the correct name.
Replacing structures
First, go to the workspace folder in src/main/resources/data and make a new folder called Minecraft or the mod_id. In this folder create another folder called structures and put into it your .nbt file named as the correct name of the original structure file. Now restart Minecraft and enjoy your refreshed structures!
Notes
- Replacing other people’s mod structure it’s funny but always remember to ask permission from the author before posting your mod.
- If two different mods change the same structure it could be some conflict