If I play Fortnite on Xbox One, do I still have access to all my items and will my progression still count across PC, Mac, Switch and Mobile?
As long as you’ve connected your Xbox One account to your Epic Games account, any purchased content and progression you’ve acquired is accessible across Xbox, PC, Mac, Switch and Mobile.
Since you are already playing on Xbox One, you will need to register full account details before accessing the progress on PC and Mac. In order to register full account details, complete the steps outlined in this article under If you have played Fortnite on Xbox One already.
* When registering account details, you will need to use an email address that is not already registered with another Epic Games account.