I built a double optin system using @joeyk excellent tutorial https://www.youtube.com/watch?v=ft3IOI1afow&t=559s
I had an issue though where the contact was not being tagged in mautic.
With @joeyk’s help we managed to figure it out.
The tag shortcode places a .gif on the page. I was using SMUSH, a cache plugin on my site. I had the lazy load option for images turned on which was stopping the tag gif from being loaded. Once that was turned off it all started working.
With cache plugins being popular I am sure many will have this issue.
PS yes you can tag website visitors using the WP mautc plugin and the shortcode [mautic type=“tags” values=“tag”] Replace “tag” with whatever tag you want eg “DOI” for double optin.