Each marketplace can have a different strategy to register vendor. Dokan Multivendor marketplace has customer migration option. That means a customer can easily migrate his customer account to a vendor account.
When a customer logged in to his account, from the my-account page he can easily become a vendor. There is a “Become a vendor” button on my-account page.
How can I remove?
It is really easy to remove this button via a simple line code. If you have a child theme then just paste the below code on your child-theme functions.php file –
remove_action( 'woocommerce_after_my_account', array( Dokan_Pro::init(), 'dokan_account_migration_button' ) );