You can use Signal with a VOIP number. Do the one-time registration and that's it. Or you can get yourself an anonymous disposable SIM (unless illegal in your c

You can use Signal with a VOIP number. Do the one-time registration and that's it. Or you can get yourself an anonymous disposable SIM (unless illegal in your country), register the number and keep hold of the SIM if you need to re-register the number in the future.