How the vendors can add Gift Cards in Magento 2 Mobile app?

First of all, you must install the Magento 2 Multi Vendor Gift Card module on your website.

With the help of this module, vendors can add gift card products to the marketplace, and the customers will buy the gift card products and use the received gift card code as a discount on the purchasing products.

Now, if you want to achieve the functionality in the Magento 2 Multi Vendor Mobile App. This will come under customization(A paid service).