Excellent reply from renojim (as usual). But for those subscriptions made through a third party (Roku, Amazon, Hulu, Sling, etc.) where the channel has not provided an alternate means of access...
If you want to be able to use the subscription on multiple platforms, subscribe directly with the channel on its website. You'll than have an account with the channel, not with some third party, and you'll be able to view it on any platform supported by the channel -- via browser on a computer/phone/tablet, or on any streaming device or smart TV for which the channel has provided an app.
Can second the idea of NEVER subscribing through a 3rd party.
I just got a Fire TV 4K Max ($25 on Amazon for Prime members for a limited time) as a backup to the Roku's I have, just in case the Roku service has a meltdown. Had no real issues, beyond trying to remember the correct email/password, on all of my subscription services.
