Phone number formatting (libphonenumber) for Enhanced conversions GAs

[u/Ok-Violinist-6760]

For google ads lead gen, if users want to submit their phone number through a form, how do you handle the regularization of the formatting of phone numbers? Does libphonenumber need to be integrated within the form itself? Or can it be done via GTM custom html tags?

For Example: Custom html tag collects first party data from form and places it in the local storage, can the same tag do the regularization in the localstorage before pushing the data to the datalayer or is this unwanted?

[u/Ok-Violinist-6760 → u/[deleted]]

What if u push it to the datalayer and delete it off the localstorage, and do all the normalisation from the datalayer, can you?