There are two general approaches you can take to creating a target audience: specific and broad.
Targeting broadly essentially means that you're mostly relying on the Facebook delivery system to find the best people to show your ad to. This approach can lead to us finding potential customers you never would've known about otherwise. Even though you still have to use at least a few basic targeting parameters, it's a good approach if you're not sure who you want to target.
If you target broadly and then check Audience Insights or ads reporting, you can learn more about the types of people we found for you and how they reacted to your ads.
For example, a business running a large-scale brand awareness campaign may want to target broadly. It could target people 18-65 years old in the United States.