Auto-filling Phone number in a text field

Site URL: https://www.airplushvac.com/contact

Hey team,

I tried using this JavaScript code block below based on another forum response to auto-fill saved phone numbers within a text field:

phoneField=document.querySelector("some query string here");
phoneField.setAttribute ("type", "tel");

This doesn't seem to work for me when I target the CSS Selector in place of some query string here.

Can anyone enlighten me as to what I'm doing wrong? I'd like to have this autofill function work.

Thanks!