How can I use the shortcode to update a user's field in a custom page?

Hello everyone.
I use the Frontent Submission in order to use the shortcode in a custom "profile edit page" where I need to fill an image field .

The image field is the following
https://app.screencast.com/016a2IKW8wGib
I would like to know if there is any way of sending the user id via the shortcode because when I click the submit button it creates a new post rather than save the user meta.

Is there any way to make the shortcode understand that I need to edit a specific user id?

Is there any hook I can use after hitting the submit button?

Thanks a lot!
All the best!
Archimidis