Facebook Boosting: Ads that you build from already-published organic posts on your Facebook page are called "boosted posts." You can get more messages, video views, leads, or phone calls by boosting a post. Also, you might be able to connect with people who aren't already following you but are interested in your page or company. If you need to generate social proof before putting your content through Facebook Ads Center or if you're pressed for time, you may choose to boost a post.
Facebook paid Ads: By audience targeting, businesses can use paid Ads to communicate with the customers who matter most to them. If you want to launch a new campaign, you can update, repurpose, and retarget an old post using the Facebook Ads Center.
What’s the big difference? While the Ads Center allows you to select particular targets like leads and sales while boosted posts allow you to concentrate on website clicks, page interactions, and local business promotions. Although people often confuse the two, there is a very distinct difference.
The short Answer: A Facebook paid Ad is a more carefully planned campaign established in Facebook Ads Center, whereas boosting a post is a quick method to pay for an existing post on your Facebook page. If promoting brand recognition is your ultimate goal, you can consider boosting a post. If you want to drive traffic to your website or have another goal that is not brand awareness, visibility, or audience growth on Facebook, a Facebook Ad may be a better option.