In order to implement the Target Audience feature for your A/B testing, you need to update your to the Purchasely SDK to version - 3.4.0.
Once you meet the pre requisite, you can segment your mobile application users based on their attributes. To achieve this,
You can use either built-in user attributes or create custom attributes in the Purchasely console
Refer to this article to know the list of built-in attributes and how to create user attributes in Purchasely
You will need access to the values associated with those attributes. Your developers should pass the value for those user attributes through the SDK