Do not download "Photoshop CS6 2020" from third-party sites. Use one of the legal, safe alternatives above. If you need CS6 specifically for legacy work, you would need an original installer from a past legitimate purchase (with a valid serial key) – but it may not run stably on modern Windows 10/11 without compatibility issues.
As for downloading Photoshop CS6 for PC in 2020, I have to advise that it's not recommended to download older versions of software from unofficial sources, as they may contain malware or viruses.