How to remove a virus from an Android phone

Almost every Android infection arrives the same way: as an app someone installed deliberately, usually from outside the Play Store, usually because it promised something free.

Start in safe mode

Hold the power button, then press and hold Power off until Reboot to safe mode appears. Safe mode starts Android without third party apps running, which stops a misbehaving app from interfering while you remove it.

Find what changed

Open Settings, then Apps, and sort by install date. The thing causing the problem is almost always something added shortly before the symptoms started. Look for apps you do not recognise and apps with generic names like System Service or Update Manager.

Take away its permissions first

Some apps grant themselves device administrator rights, which blocks uninstalling. Go to Settings, Security, then Device admin apps, and turn off anything suspicious. Then uninstall normally.

If it will not uninstall

An app that reinstalls itself usually has a second app installing it. Removing only the visible one leaves the loader in place. A scan is faster than hunting for it by hand, because the pair are often named to look unrelated.

Afterwards

Change the passwords for anything you signed into on that phone, starting with email. An app with accessibility permissions could read what you typed.