How to converting STD file with Mac?

Hello fellows,
How to perform std file conversion? My current operating system is Mac, the company bought a computer with this built in operating system. I am an administrator for our company website and they are expecting me to do technical stuffs such as encoding, networking, troubleshooting, converting files and more. Can share some idea about std file converters? Thank you.
Regards,
Ericson Eric.
