The Custom Audience feature on Facebook allows you to target people who are your target audience that are on Facebook. Sources such as website traffic, customer lists, and customer engagement results can be used to create custom audiences from people that are already your connections on Facebook and who are familiar with your business offering. The following are the four types of Custom Audiences that you can create on Facebook- Website custom audiences, Customer list custom audiences, App activity custom audiences, Engagement custom audiences. The benefit of growing your business is that you can use your Custom Audiences to create a Lookalike Audience to target users with similar interests.