Question: how to generate ppk file from pem?
Answer: Download Putty and puttygen from - here.
Use puttygen to convert . PEM file to . PPK file.
Start puttygen and select “Load”
Select your . PEM file.
Putty will convert the . PEM format to . ... 
Select “Save Private Key” A passphrase is not required but can be used if additional security is required.