The one thing anyone can do to make everything smooth and easy is sign a message with a wallet you control. If you can't sign a message with your shipping info, you will create delays for yourself and slow me down too.
Next, when signing a message, most of the time I have no clue what the actual message is, it's hard to guess and in order to verify, it has to be precise.
For example:
You should send me something like this:
Address: 1L6ZbfnfMmcqFPJ97aZNqozKZQjDWppcmj
-------------BEGIN---------------------
Please ship to:
John Smith
123 Way Ave
City, IL 60188
--------------END----------------------
Signature: INB7sIYNK8eJ/qZZ/wS/l5nYjjdkOx6zXLZvjUMBGw/l+sjYfRcWgDi4B/+/Op9Y/uRqupjtpjSdMB2TLK96FBw=