YITH WooCommerce Quick View allows the users to get a quick view of the product in which they are interested. The product details will be shown in a popup, so they don’t need to leave the current page.
To make the two plugins work well together you’ll need to enable Enable image zoom in Quick View -> Products -> Content Options. Once enabled it allows you to enable the zoom feature also in the product “quick view”.
YITH WooCommerce Watermark lets you apply a logo or a watermark to all your product images. The Zoom Magnifier plugin uses a different image size, so the Watermark plugin will add this specific image size in the available image sizes.
In order to make the two plugins work together, you will only have to activate the premium version of both of them.
For more information on how to set up the watermark plugin, take a look at the full documentation here.