How to edit calling number

You cannot place a cursor in any area of the phone number sequence like you can when typing/editing text in other apps. In the Phone app (the picture that you posted) you have to use the X (Delete) key which is located to the Right of the Green phone Dial icon. You can continue to tap the delete icon until your mistake has been deleted and then complete typing the balance of the phone number.

Axel F.

You will have to start with +375. In your example if the phone number has been entered without the prefix, then you will have to delete the number and then add type out the whole number with the prefix.

Axel F.