How to check which platform I used to subscribe to Fortnite Crew?

Epic Games Launcher 

1. Open the Epic Games Launcher and sign in.
2. Hover over your display name and click Account.
3. Click Subscriptions on the left-hand side.
4. You can now see the platform(s) on which you’re subscribed to Fortnite Crew..

Web Browser 

1. Open www.epicgames.com (Opens in a new tab)
2. Click on Sign in in the top-right corner and sign in with your Epic Games account.
3. Hover over your display name and click Account.
4. Click Subscriptions on the left-hand side.
5. You can now see the platform(s) on which you’re subscribed to Fortnite Crew.