# If you want to add your existing SSH key
# to your OpenSSH client in Windows 10/11 do the following;

Copy your existing id_rsa key (and possibly id_rsa.pub)
into C:/Users/[your user]/.ssh/

Resulting in C:/Users/[your user]/.ssh/id_rsa 
        and  C:/Users/[your user]/.ssh/id_rsa.pub