By default, If vendors are paying with MVX paypal marketplace or MVX stripe marketplace, the payments are getting paid in real time i.e. they are becoming vendors without any admin’s approval.
Now if you still want to make vendor as a pending vendor, vendor after successful payment, then add this code in the finction.php of the current active theme :
add_filter('admin_has_given_capability_to_approve_vendor', '__return_false');
