You can sell products that are out of stock or not available yet by setting them up as preorders. You can use preorders to help you forecast the demand for a new product that you're releasing, or to create customer excitement around a new release.
Depending on the preorder options that you offer, you can collect full, partial, or no payment at the time the customer places their order. Collecting payments stores your customer's payment method, and then you can fulfill and collect the remaining payment at a later date.
To use preorders, you need to install a preorder app from the Shopify App Store and then manage preorders in the Shopify admin. To set up an item for preorder, you need to complete the set up in the app that you install.
If you uninstall a preorder app, then any preorder data (excluding customer payment information) that you've created in the app is deleted after 48 hours. If the app has a backup mechanism in place, then you can restore the data at a later date.