I checked the Apple Style Guide 2013, Microsoft Manual of Style 4th Edition, and the Apple, Microsoft, and Google support sites for examples of their documentation. It looks to me like Apple and Microsoft don't reference the control directly for end users. Instead, they prefer you to describe the action or service for that control, though both might allow button if necessary.
switch (n.) Avoid using to refer to an interface element that offers the user two mutually exclusive choices--usually on and off. Instead, describe the action the user takes.
Tap to turn on Location Services.
Tap to turn airplane mode on or off.
User lowercase for on and off, even though the control options are uppercase.
Avoid using the term slide; use tap instead.
Apple Style Guide 2013, p.144
If your iPhone, iPad, or iPod touch won't connect to a Wi-Fi network
...Tap Settings > Wi-Fi and make sure Wi-Fi is turned on....
Set up a Wallet PIN on Windows Phone
- Turn on Wallet PIN [Toggle switch image], enter and confirm your new PIN (it must be at least four digits), and then tap Done.
Google appears to use the term switch
Connect to Bluetooth - Nexus Help
3.Touch the switch to turn Bluetooth On or Off.