How Vendors Setup SMTP in Magento 2 Marketplace Mobile App?

Well, first the Magento 2 Multi Vendor Marketplace admin must have installed the Magento 2 Multi Vendor SMTP extension on their website.

This allows the marketplace vendors to setup and configure their own SMTP for sending emails  to their customers.

Now, if you want the similar feature where the vendors can configure their SMTP using the Magento 2 Multi Vendor Mobile App, this will come under customization(A Paid service).