I am trying to do a personal project, unfortunately I am not an expert. Specifically, I am creating a classifieds site. For each ad, I would like the relative page to have a url containing the telephone number entered by the user when filling in the form for the ad.
I have tried the various plugins that manage permalinks, but none of them show the telephone number among the available tags.
How could I do this?

The theme I am using is listeo.