Apple mainly uses iOS, which is a typical jail, to impose censorship through the Apple Store. Please refer to Proprietary Jails for more information.
Google offers censorship software, ostensibly for parents to put into their children's computers.
On Windows and MacOS, Chrome disables extensions that are not hosted in the Chrome Web Store.
For example, an extension was banned from the Chrome Web Store, and permanently disabled on more than 40,000 computers.
Google censored installation of Samsung's ad-blocker on Android phones, saying that blocking ads is “interference” with the sites that advertise (and surveil users through ads).
The ad-blocker is proprietary software, just like the program (Google Play) that Google used to deny access to install it. Using a nonfree program gives the owner power over you, and Google has exercised that power.
Google's censorship, unlike that of Apple, is not total: Android allows users to install apps in other ways. You can install free programs from f-droid.org.
The Nintendo 3DS censors web browsing; it is possible to turn off the censorship, but that requires identifying oneself to pay, which is a form of surveillance.