SwiftyTemplate

Custom Templates Directory

~/Library/Developer/Xcode/Templates
mkdir -p ~/Library/Developer/Xcode/Templates/File\ Templates/Custom

Xcode Default Templates Directory

/Applications/Xcode.app/Contents/Developer/Library/Xcode/Templates/File Templates

Xcode Custom Code snippets

~/Library/Developer/Xcode/UserData/CodeSnippets/

Xcode 12

Custom templates directory

/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/Library/Xcode/Templates/