Where ? Like I have sponsor block on a desktop but on my pixel I don't have it and would like to have the option. Have the yt premium but don't see the option to skip sponsors.
If you double tap to skip 10 seconds during an ad read, it should appear as a button in the bottom right. It does not pop up proactively. It's algorithmically-based on which parts of the video get skipped most often by viewers.
Firefox for Android supports desktop extensions, including Sponsor Block and uBlock Origin.
There's also Tubular, a YouTube client and fork of NewPipe with Sponsor Block built-in. If you don't mind installing apks from outside the Play Store: https://github.com/polymorphicshade/Tubular