To access Reach optimization, use the Awareness objective and “Maximize reach of ads” performance goal. Reach optimization allows you to show your Facebook ads to the maximum number of people while using a frequency cap.
When you use this option, Meta will not optimize distribution for a specific action. As a result, your goal should be awareness when targeting a large audience, since you are unlikely to get the actions you desire. Otherwise, consider targeting a very small and relevant audience if you’re looking to get conversions.
Some related reading:
