To become a tester, you generally need to be invited by the app developer. Developers can provide a link to join their testing program or email you an invitation. You may also join a testing program directly if it's open to the public. A Play Store Tester is someone who participates in testing pre-release versions of an apps on playstore tester. These testers provide feedback to developers before the app is officially published or updated on the Google Play Store. Developers often share testing links on their website, social media, or through email. If you're interested in testing a specific app, you might also find the link in the app's description on the Play Store, under the "Join the beta" section if the beta program is public.