With Importify you have the ability to import product to a specific collection using the Importify extension.
Follow this guide:
Visit the product page URL
Click the "add" button on the top left side of the screen
Change the Title, Description, Pricing etc..
Scroll down and find the "Collection" field, add the collection you want this product to be linked to and click the import button.
When you create a collection, make sure to pick the "manually select product" option else it won’t appear in the list when using the Importify extension.
check this screenshot below