To purchase a forum backlink on Fiverr, you first need to find a seller offering such a service, which involves searching for "forum backlink" or related terms on the Fiverr website. You'll then need to review the seller's offerings, which vary in quality and price, and use Fiverr's payment system to complete the purchase once you've selected and customized an order. However, be aware that many forum backlink services on Fiverr are of low quality, may violate Google's guidelines, and can be detrimental to your website's ranking.

Faruk Hosen, known online as "seobmfarukzaman," has previously offered forum posting services on the freelance marketplace Fiverr. To inquire about or purchase a service, you would typically need to contact him directly through the platform he is using.