Facebook offers several ways to sell products (physical and digital) as well as services. The easiest one is Facebook Marketplace. This is usually for local selling. There are no requirements for this feature, you just go to Facebook Marketplace and create a listing by uploading photos, setting your price, and waiting for buyers. Another method is to create a Facebook Shop, you will have to meet the eligibility criteria. Selling from your Facebook page or group is also easy. There are no requirements to meet but having a lot of followers will make easier to sell. You can just list your product on your page and wait for other users to contact you. You can boost visibility with targeted Facebook Ads.