How do I stop my phone from continuously attempting to download something

[AC Question]

My phone is attempting to download something - I have no idea what - it reports 'downloadingfile.apk' but is not getting past 9% and the down load arrow on the screen in constantly moving down - very annoying and no doubt battery draining. Please could someone advise on how to cancel this process.
Anthea

 

[B. Diddy]

Welcome to Android Central! Which phone? First, go to Settings>Security and uncheck Unknown Sources, to make sure unauthorized apps won't install (i.e., apps not installed via Google Play Store).

Chances are that you installed some adware or malware alongside some other app that is trying to download and install some other app (that itself might be malicious). Uninstall apps one by one until the behavior goes away.