Well.... it would probably depend on the phone's Manufacturer, Model and maybe even to some extent the Carrier (although I'm not certain about that last one).
On the box that the phone comes in, on the back you should see a number of symbols / icons. Among these should be something stating "Hearing Aid Compatibility Rating
My Windows 10 Alcatel Fierce XL (Tmobile branded) has an M4/T4 rating (the "T" being the one you are asking about.
Then in the Settings -> Ease of Access -> More Options you should see something like Telecoil with a slider On / Off