NOTE: As of Facebook API version 3.1 (January 2019), Page Like Ads no longer exists as their own specific ad type. They need to be created as Page Post Ads using the Link Ad creative type instead. All Page Like Ads created before January 2019 cannot be edited, but they will still work & keep delivering. If you want to make changes, you should create new ads to replace them.
Page Like Ads call for users to like the page you are advertising. Clicking on a page like ad will redirect the user to the advertised Facebook page. The ad will also display a "thumbs up" like button.
How to Create Page Like Ads
Start creating a Page Post Ad and set creative type to Link Ad
In the website URL field, enter your Facebook page URL, e.g. https://www.facebook.com/smartly.io/
Set Call to Action to “LIKE PAGE”