How is such a link built?
The link contains the destination page plus parameters: a programme ID, a publisher ID and often a click ID or sub-ID for reporting. Those parameters make every click traceable.
The visitor does not need to do anything extra; attribution happens automatically once the purchase falls within the cookie window.
Which variants exist?
Besides standard links to the homepage there are deep links to specific products, banner links and voucher codes. Deep links usually convert best because they land directly on the right product.
Voucher codes work even without a click: the code itself is the tracker, which is useful for podcasts, print and influencers.
Rules around affiliate links
Publishers in the EU must make commercial content recognisable, for example with a notice that links may earn commission. That is a legal transparency requirement, not a courtesy.
As an advertiser you define in the programme terms where links may and may not be placed, such as no paid search on your brand name without permission.
Maintaining links
Changing URL structures and discontinued products break links. A broken link costs publishers revenue and costs your programme goodwill.
Keep redirects tidy, communicate changes proactively and periodically test a sample of live links per market.