Ubisoft will be giving away free games and in-game items every day of this week. You can redeem those gifts by registering to ubisoft.com, or the Ubisoft Connect client could be used for the matter.
You can claim the Seafarer Settlement pack and legendary Bayek outfit for Eivor right now. It’s also worth noting that even if you don’t have Assasin’s Creed: Valhalla, you can claim the gift right now and use it after you get a copy of the game. The gifts are available for every platform.
Make sure to claim every day’s gift on that day, after the time’s up for that day the gifts will be gone forever. In-game content will be available for all platforms but games will be PC only. We don’t really have a clue on which games will be free since no statement from Ubisoft side was made.