PFX files usually have extensions such as .pfx and .p12. PFX files are typically used on Windows machines to import and export certificates and private keys. When converting a PFX file to PEM format, OpenSSL will put all the certificates and the private key into a single file.
The recommended SSL Converter to convert CRT to PFX online.
What is the difference between PFX and CER?
CER is a file extension for an SSL certificate file format used by Web servers to help verify the identity and security of the site in question. SSL certificates are provided by a third-party security certificate authority such as VeriSign, GlobalSign or Thawte. This certificate contains information about the certificate's owner along with public and private keys.
PFX - stands for personal exchange format. It is used to exchange public and private objects in a single file.