Xcode Snippets are snippets or templates of code that can help you in your programming routine. Usually when you update your Xcode, nothing happens with snippets. But sometimes, after purchasing new Mac, reinstalling Xcode or Updating OS you can have troubles with finding your snippets. It is a good practice to transfer your snippets to the safe place before moving to the new version of Xcode or before Mac OS Update.
If you want to know, where is the folder with Xcode Snippets on your Mac, here is the answer:
Open Finder on Mac
Press Go > Go to folder
After that copy files from this folder to a safe place. Later when you will install the new version of Xcode, again go to ~/Library/Developer/Xcode/UserData/CodeSnippets and paste them there.