This Help Centre article shows affiliates how they can find out whether or not an advertiser's program allows Paid Search affiliates.
Once on the advertiser profile page, scroll to the bottom to view the advertiser's Program Restrictions. Here, it will be shown in green which types of traffic sources that affiliates can promote with on the program. Displayed in red are the types of traffic sources that are not allowed on the advertiser's program.
If the advertiser allows paid search, then any terms and conditions surrounding paid search activity will be listed below.
For information on how to apply to advertiser programs, please view our Help Centre guide here.