Convert a .pem private key file to a .ppk one with PuTTYgen

Download and install PuTTYgen from here.

Step by step

• Launch PuTTYgen
• click "Load" ("Load an existing private key file")
• in the extension list choose "All files (.)"
• navigate to the folder where your file is located
• select your myKeyName.pem file
• you get a success report, click "OK"
• click "Save private key" without passphrase
• save it as myKeyName.ppk
• close PuTTYgen