Closed Captions on Roku will not turn off and can't be moved from the middle of the screen.
Is this on a Roku player or a Roku TV? If it’s a Roku player, and you can’t turn them off on the player, then they are probably coming from the TV.
This is a Roku TV. Captions on Roku home page shows captions turned off. Captions in utube TV do not show as an option when asterisk is pushed. And nowhere is moving the caption around offered.
The Roku default method of accessing your overall Closed Captioning options from the Roku home screen is via Roku menu path "Settings > Accessibility" and use the "Subtitles & Captioning" section on the right of the screen.
While viewing a program, you can also press the * key on your Roku remote and examining the options presented which can vary depending on what that channel supports. You may have to look in Accessibility.
But more and more channels are not using the Roku default, and CC can only be set while viewing the program. These channels substitute their own method of access -- I'm guessing this is so they will have consistent controls with versions of their app running on platforms other than Roku. Often these options are accessed by pressing the up and/or down cursor control keys while viewing the program to pop the channel's own control options on the screen.