Let me also add that there are premium services you can subscribe to directly such as Netflix, Major League Baseball TV, and a bunch of others. When you do this, you can view the channel on any platform for which they provide support (computer via browser or dedicated app, mobile device app, apps on various streaming devices) by logging in using your direct account credentials.
Some of these have also made arrangements with third parties (Roku, Hulu, Amazon, etc), enabling you to subscribe to them through the third party. This has the convenience of consolidated billing through the third party, but with a serious drawback. Typically you can view the channel ONLY through the third party handling the subscription. In Roku's case this means you can only view a premium channels with a subscription through Roku on Roku's own The Roku Channel. In most (all?) cases If you subscribe through one third party platform and try to watch on another, you cannot log in and view the channel. Also, if you have any problems and need support you often find the channel and the third party just point fingers at each other and it makes it difficult to get help. Personally, I subscribe to all my premiums directly with each service to give maximum flexibility and avoid some potential hassles.
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
If this post solves your problem please help others find this answer by clicking "Accept as Solution.".
Streaming Stick 4K+ 3821 | Streaming Stick+ 3810 | TCL Roku TV 43S245/C107X