I would like to write about knowing the file singture to identify the file type >>> this step will help you to detect the virues and tojans 

worms etc. before we start this we have to let you be aware about common files that widely used by hackers>

these are the common files extensions that may hackers use to hack your pc or whatever

we have to download hex editor 

drag your spouisous file into the middle of this software 

e.g

cccc.html 

we know that file is html file  ....

download hex

editor

https://mh-nexus.de/en/hxd

cyber_c0der