To purchase or add premium subscription channels directly on your device, follow these quick steps: From the Roku Channel Store

If you buy a premium subscription through Roku, you generally have to watch it on a Roku device or through the official Roku Channel app. You might not be able to use those credentials to log into that network's native app on a computer, smartphone, or competing device like an Apple TV.

Below is an evaluation of the pros and cons of purchasing channels through Roku, followed by step-by-step instructions on how to do it. ⚖️ The Review: Pros & Cons

Click on the network banner you want to add and follow the on-screen prompts to confirm the recurring monthly purchase.

Note: To prevent accidental or unauthorized purchases by children or guests, it is highly recommended to go to your online account settings and set up a required Roku PIN for all transactions. The Roku Channel Review: A Streaming Mishmash - PCMag

Content from your premium channels often populates directly into the main Roku Channel interface, making searching for shows much faster.