Sitepages
Sitepages runs advertising for small businesses. A business writes its ad once, chooses where and for how long, and Sitepages places it on Facebook and Instagram, then reports what came of it.
If you were asked to connect your Facebook Page or ad account, you were sent here by a business that uses Sitepages for its ads. Connecting lets that business's ads appear under your Page's name. You can disconnect at any time from your Facebook settings.