Your question isn’t too clear, but if there are some subdirectories where you want different gitignore rules, you can just create a new .gitignore in that directory.
Say you have:
project/.gitignore project/stuff/.gitignore
The .gitignore in stuff/ will override the .gitignore in the root directory.
git help gitignore or man gitignore has quite a bit more information about what’s possible.