: Long-press any empty space on your home screen and tap to open the Galaxy Themes Store . Note that while Samsung phones have robust theme support, some Galaxy Tab models may be limited to icon packs and wallpapers rather than full system-wide themes.
: You can find "Theme for Lenovo" or "Lenovo Launcher" in the Google Play Store to add variety to the pre-installed Theme Center. Google Pixel Tablet
If your tablet doesn't have a built-in store, downloading a third-party launcher is the most effective way to apply comprehensive themes.