Tnumbers are app-based works via internet. Mobile nymbers are SIM-based works using carrier network.
Yes, all calls and messages also free
Calls can be made between Tnumber to Tnumber only. You can't call mobile numbers from Tnumber
if you know someone's Tnumber, first send a contact request. If they accept? you can call them from then
No, you won't. Tnumber does not need any SIM Card or documentats. All you need is smartphone to install the Tnumber App.
Tnumbers can not be used for emergency calling.
Yes, Tnumbers are available for global users and India as well
Yes, you can remove their Tnumber from your contacts. They won't be able to call