There's no one answer to this question since everyone's needs are different. Some people may just need a basic antivirus program, while others may need something more comprehensive like a security suite. Some people may also use additional security measures like a VPN or firewall.
If you're not sure what you need, a good starting point is to read some reviews and compare different programs to see whatfeatures they offer. You can also ask people you know for recommendations. Once you've narrowed down your choices, you can try out different programs to see which one works best for you.