Malicious actors often take a legitimate, free app (like a picture resizer) and "wrap" it in malware. You get the tool you wanted, but it runs a silent script in the background.
Sideloading is the process of installing an app from an unofficial source. While it has legitimate uses for developers, for the average user, it opens the door to: Download Picture Resizer1313 DZAPK COM apk
Your photos and files are encrypted until you pay a fee. Malicious actors often take a legitimate, free app