Well, becoming a seller in Magento 2 store is easy. You must have installed the Magento 2 Marketplace Multi vendor module. As in the default Magento, when a customer registers himself and logs into his account panel he just has the customer dashboard. Now, after you have installed the marketplace, the customer will have a Become Seller menu option.
Clicking the link will bring the section to add the shop URL. Enter your shop URL and check the option to become a seller and click the save button.
After the installation of the Magento 2 Marketplace Multi vendor extension, the customer will have a menu link to become a seller. Clicking that tab will send a request to the admin of the marketplace after whose approval the customer will have the marketplace dashboard of seller.
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