How to open line my ipad
How to open my sim in iPad
iPad Pro, iPadOS 16
Question marked as
It’s not clear exactly what you’re asking ?
FYI, an iPad can not REPLACE a phone (it can’t “open a line” to make phone calls by itself, even with a SIM installed)
If you’re asking how to physically “open” the SIM tray on your iPad, see this article:
Remove or switch the SIM card in your iPad - Apple Support