Stalkerware is a term given to apps that let someone spy on your smartphone activity. They’re also called « spouseware » because they tend to be used by abusers to spy on their partners.
Most of this software ends up on a device through one of two ways: A phishing attack (email or text links that contain viruses and trick you into clicking on them by pretending to be something/someone else), or physical access to the device.
The article is a good read with tips for people in abused relationships.
Check It Out: How to Find Stalkerware Apps on Your Phone
