Basically our smartphone does not require any antivirus applications to secure our handset.
Though there are so many apps we can found on play store for free. But free means they do not protect our smartphones from viruses so I prefer u to dont download any free antivirus software cause it wont pritect but shows u that it is deleting virus files. I did used those free softwares but they were all fraud. So dont use any free antivirus app in ur android.
But a computer strongly need a better antivirus software to protect ur data. If you using pc for normal use like gaming chatting or surfing then u should go with AV software which is arount 1000rs a year and easy to use. I also use that software to my pc. It dont need heavy data ti update. But if ur using laptop or pc for ur office use then you should buy Quick Heal antivirus cause it is better antivirus software to use than others. Bit expensive but it protects ur data from being stolen betterly. And it also requires around 900 MB per month of update.