Hello
There are some good free antivirus programs, it all depends on what you want.
Personally, I'd say Kaspersky Free, Bitdefender Free or Microsoft Defender.
Kaspersky: Excellent Web protection, excellent malware database, excellent behavioral blocker.
Bitdefender: Very good Web protection, malware database a little behind, but Active Virus Control easily makes up for it. However, it may have an impact on performance.
MS Defender: Integrated into Windows, very good database. You can complement it with WHHLight to have a fortress