How to add a Phone 📞 number to IPAD without an IPhone 📱

I don't believe that you can. The iPad is not a phone and therefore requires an iPhone for cellular calls and SMS/RCS messaging. Messages does not require cellular and therefor iPad can do that on it's own with an Internet connection.

Here are some articles to get you started once you have an iPhone to use alongside the iPad:

Use iPhone to allow calls and text messages on your iPad - Apple Support

Add or remove your phone number in Messages or FaceTime - Apple Support

If you have an iPad with a cellular data modem, and an active cellular plan, there may be an associated number.

However, you cannot use a cellular iPad, by itself, to make or receive cellular phone calls, or to send or receive SMS/MMS or RCS messages. The cellular modem is for Internet data only.

To reinforce prior replies:

An iPad can’t be a phone.

Without a “linked” iPhone It can never send SMS/RCS texts or make telephony “phone calls.”

It can communicate via WiFi or Mobile “Data” channels; services which include FaceTime, iMessage, and various VoIP apps.

Why would you need an iPhone to add a number? Just add it in the Contacts app, the same as you would on a phone.

Exactly what are you hoping to accomplish?