Notice in the picture the icon image for certs has either Standard or Personal written on it. What is the difference? The most recent time I'm working on it, I produced only icons with "Personal" on them. I don't know why. What is the difference? How are both produced?
I would say it because your.p12 files include your private key. And the.cer files only contain the certificate.
Pem is a container format. It can include just the public certificate, or public key, private key, and root certificates.
p12 is commonly used to bundle a private key with a certificate. "Making it personal".
.cer is just the certificate
Check this answer for how to create pem files
