You can use your Google or Apple ID to sign in to all Mozilla products and services, with the exception of Firefox Sync.
For security purposes, Firefox Sync requires a password to be set and associated with your Mozilla account so that your Sync data can be encrypted. When you authenticate your Mozilla account using Google or Apple, we don’t have access to or store your third-party authentication password, so we will not be able to encrypt your data.
You can still use your Google or Apple ID to sign in to your Mozilla account, but you’ll need to set an additional password to use Firefox Sync. We’ll prompt you to set a password when you want to access Firefox Sync, if you don’t already have one set.