The tablet does not have a sim card slot. Want to make a phone call and send a text message, can I use usb to access the Internet and expand the sim card holder?

If your tablet doesn't have a SIM card slot, you decide that you can't surf the Internet directly with 3G. Of course, it is even more impossible to make a phone call. You said that using USB network card can solve 3G Internet access. Whether you can make a phone call depends on whether the USB network card you use can make a phone call directly, or whether there is software to support the phone call.