Fortunately, the Google Play Store has a neat feature known as "Google Play Protect." This function allows you to scan your phone for applications from untrusted developers or apps that cause problems. Keep in mind that this feature does not eliminate apps that provide ads—it just blocks apps used for malicious purposes. Click the three horizontal lines in the upper right-hand corner of the Google Play Store and tap on 'Play Protect' to run a scan of your phone's downloaded apps. You can also set Play Protect to automatically run scans by opening Play Protect and tapping the settings cog in the upper right-hand corner. Toggle the options on, and the Google Play Store will continuously scan the applications you download.