Your Recording Line is a private line that you can use for recording phone calls made to your real phone number. It is also a phone number on its own that you can use to call and record while staying anonymous.
To find out your number: You need to call someone FIRST and then your contact will be able to see your number to text you back. Until you text or call someone, the Recording Line is not known.
Once you have called someone, a number is randomly assigned and becomes the permanent number between you and the recipient.
For a more permanent number that you can keep or share: You can select a Premium number for this. Tap on top left button in (Menu) -> Get Premium number and choose a premium number.