Update a menu_page

Hello everyone!

I have a question: I made many menu_page (with add_menu_page function) to add additional data to the user directly in the table wp_usermeta. But i don’t understand how make the database update. I think i should insert a submit button and an action that update the wp_usermeta table. It is corect? Which code I have to use to insert the submit button?
And in the action that update the menu_page, which $tag I have to use?

Thanks for your help and sorry for my english!