You can generate a Pre-Save and/or Play Link by clicking the Create Play Link button on a product in your Catalog. If you do not see this button, contact firstname.lastname@example.org to have it enabled.
Once clicked, a static link will be generated and provided in the Play Link field shown above. You may share this link on social media or anywhere else you're promoting the product. When someone clicks it prior to the Release Date of the product, they'll be taken to a Pre-Save page:
If Pre-Save or Pre-Add is clicked there, the product will automatically be added to the person's collection or library at the given music service.
Once the Release Date of the product passes, the same link will lead to a Play Link page where they can choose which music service to stream or purchase a download from.
Note: If you use Change Requests to change your Release Date on a product at any time, it will also switch the date when your link changes from a Pre-Save to a Play Link.