If you would like to convert .ppk file into .pem file, the process are given below:
1) Open terminal and make Your login.
2) sudo apt-get install putty-tools.
3) puttygen /var/www/html/abc.ppk -O private-openssh -o /var/www/html/abc.com
4) chmod 400 /var/www/html/abc.prm
