I (on mobile) have an option in the account settings to connect my account, but my friend (on PS4) doesn't have it as you can see in the photo.
What can he do to link his account on the Ps4?
What can he do to link his account on the Ps4?
Nothing. PS4 can't. They use the Playstation account
Only iOS, Android and PC can activate Crosssave via an account
The Playstation version does NOT offer cross-save and with the many reports about hacking and account theft, that's better!