Which is the best software for virus protection for free?


There's a lot of free options like Avast, but really if you are using any free ware you're leaving yourself open.

Keep up the work.
Depends on the use of your computer. For the most part, there's is not a necessity to deploy a premium protection suite on our personal or home computers, a free antivirus is fine and enough. Just check the most used free antivirus like Avira, Bitdefender, AVG and more in Top 5 Free Antivirus for 2018. I would also suggest you read more reviews from different places before installing a protection suite as the major drawback of these freewares is the ads bundled with them.
However, in another case, a paid antivirus would be a wise choice in the case where you're running a business that requires an absolute safe environment in your computer.