Smart Links allow you to set up referral links for individual pages, e.g., a single product or a collection, and track their performance in your Analytics module. Partner Links which are generated upon registration, are indeed Smart Links for your store's homepage.
Setting up a Smart Link
This is where the link's most important information is. Have in mind that you will not be able to change the slug once it's created.
The Default destination should only contain the direction of a page. For example, if you want a referral link to redirect to the product, you simply insert the part of the URL that is after '.com/ '.
Partners will see a link's name and description in their portals (highlighted below).
Here you can specify which partners will see this referral link. You can create links for every, a few, or an individual partner. While creating a smart link for specific partners, make sure to uncheck the shared with all partners option.
This allows you to edit redirection within the link based on the customer segment, for example, device a visitor will be using, even though the referral link redirects to the PC version of the product, customers using mobiles will be redirected to a mobile version of the product. You can change destinations based on multiple criteria like customer country, total visits, partner group, etc.
Well done! Now you know everything about Smart Links.