As far as I know, we don't have an established equivalent for this in Farsi, so we should come up with the best possible term to convey the meaning

Co-registration occurs when a web visitor registers for a product or service on a third party website. ... For example, a web visitor decides to register on a website for a free product, free Email or a newsletter. After they enter their contact information, a list of third party offers follow.

Co-registration is an important type of marketing in that you can use it to target a specific demographic or customer subset. Depending on the scope of your marketing efforts and what websites you partner with, co-registration can be less expensive than other types of marketing, such as television and print advertisements, which don't allow you to target one type of specific customer. Also, with co-registration marketing, you don't need to worry about increasing the traffic on your website to grow your subscriber base. Instead, your partners' website traffic suffices to funnel potential business toward you.