Volte or wifi call
Dear sir, with due respect to inform you that I need volte & wifi calling facilities at i-phone 5s & what is the procedure ?
This is not a chat service. This is a user to user support forum and Apple does not participate here. You type out a question describing your problem and any troubleshooting steps you have taken to fix it, and wait for one of the volunteer users to read it and one to answer it.
Regarding wi-fi calling, you need to contact your carrier. They control wi-fi calling if they support it. Then you can go to Settings>Phone, and turn it on.