Lookalike Audience can help you reach audiences that share commonalities with your existing customers. It could help you deliver your ads to audiences that are interested in your product.
The model will use algorithms to study the attributes of the custom audience you create. For example, we will analyze attributes of the users from the Custom Audience type you selected, such as demographics, location, operating system, interests, etc. Then, the model will look for users who are similar and have the potential to convert.
There are three lookalike audience size options (Narrow, Balanced, and Broad), which provide flexibility based on your distinct marketing strategies.
Creating Broad Lookalike Audience increases the potential reach with moderate similarity between the lookalike audience and the source audience. Creating the Narrow Lookalike Audience helps find users who have the highest level of similarity with your source audience but the size of potential audiences in Narrow Lookalike will be relevancy smaller than Broad/Balance Lookalike.
The size of the Lookalike Audience is based on the user base of the market you specified and the scale you selected (Narrow, Balanced, and Broad).
The minimum size of the source audience for Lookalike creation is 100.
Refer to Create a Lookalike Audience for creating Lookalike.