Hello, @ForjarEmpresa,
1- To add the background image you have to log in via vendor on the site and then from the store settings you can add the banner image: https://postimg.cc/56v0fRLB
2- To add the profile image navigate to the Dashboard>> multivendorX >> Vendors >> Staff and add the image there: https://postimg.cc/KRfQzJnW
3- From the store settings in the vendor dashboard you can add/create the policies tab. https://postimg.cc/5X4MD73N
Kindly first delete the page and then create it again after that go to this link there you will find all kinds of shortcode of this plugin: https://multivendorx.com/list-of-shortcodes/ add the one you want on the page and then check back to your site after clearing the browser cache.
Regards 8Themes Team.