Creating one

npx @react-native-community/bob create name-of-module

Adding iOS CocoaPods dependencies

Go into the generated native module folder, edit the name-of-module.podspec file. Add s.dependency "PodDependencyHere" for each dependency right before the end

Modular headers (not sure if this is required): go to example/ios and edit Podfile, and do use_modular_headers! or :modular_headers => true for a dependency

Adding it to your main RN app

Go to Podfile in the main project, add pod 'name-of-module', :path => '/path/to/native/module/where/the/podspec/is'
*i tried adding , :modular_headers => true here but it didn't work so I put use_modular_headers! globally