Which antivirus program is good and free?

I finally bought a laptop and before I got any viruses I wanted to download an antivirus program. Can anyone recommend something good?

If you have a Windows 10 computer, you do not need any extra antivirus software. The integrated Windows Defender is more than good.

The human mind is free and in most cases also good. Nowadays you don't actually need any anti-virus software anymore, Windows on-board means are pretty good and if you don't act completely stupid, you can do it all well.

Install adblock, but that's all you really need

Plus Brain.exe and nothing can go wrong… ☺☻☺☻☺

https://www.bitdefender.de/solutions/free.html is good and free.

Only one thing has to be clear to you - and this generally applies to all free products: In the event of an incident, you will not receive manufacturer support.
That may not be a reason for computer-savvy people - but for ordinary consumers, it can make the difference to have a human professional as a support.

Edit - don't listen to the "Windows Defender is enough" people - unlike Bitdefender or Kaspersky, the security performance in the standard settings is in no way adequate.