I'm also wondering does TCL Nxtpaper 11 have Sim Card slot and it's possible to use it as a phone. Seems that there are two versions, one has more ram and official LTE support:
https://www.tcl.com/au/en/tablets/tcl-nxtpaper-11
https://www.tcl.com/au/en/tablets/tcl-nxtpaper-11-lte
Point is, on their official website in "specifications/in the box" both list "SIM pin" available which is confusing.