PowerShell fails to interpret commands such as "which"

Question

My windows Powershell gives the expected results when interpreting commands such as "date" and "echo", while problems occur when it interprets such commands as "which" and "tail". I thought it might be that I haven't add the address of these commands to the target directories, but where can I probably find these commands.

What happens when I apply "which", with the same thing happening when applying "tail"