In some mobile phones antivirus comes preinstalled but there are many phones in which there are no antivirus so install antivirus in your mobile device to remain virus free and if you don't get the antivirus then you can download from compatible antivirus from antivirus customer service for your device.

On my Android phone installed AVG Antivirus. You can watch avg for android review. But on the PC I use Kaspersky Antivirus. There are many good antiviruses. The main thing to choose famous opinion

Antivirus are overrated! Newest Android phones don't really need them, as Google has implemented a new security mechanism starting with Oreo, and also Microooft Windows 10, has inbuilt security mechanism.

By the way, what security measures besides antivirus and firewall do you use? I read about such https://www.talk-business.co.uk/2019/04/04/safeguard-your-systems-what-to-do-to-prevent-a-business-crisis/ methods, this is especially true for business. What do you think about that?
Maybe you can recommend specific programs based on this list? I would like to know.
Thanks!