Since you are using a SIM card there is no requirement to register for A2P and you can get setup in minutes.
You will still be required to register details as you would for any normal number with whatever is required for the SIM plan you are purchasing and the requirements of that service provider in the country you are in.
These are generally a driver's license and address.
If you are setting this up on behalf of a client we would recommend that you get these credentials from your client and register the number in their name.
We recommend that you still ensure that you comply with any regulations regarding sending SMS messages as per our Terms of Service.
Please see related articles below for more information