Install OpenSSL
Open PowerShell and cd to OpenSSL install location -
C:\Program Files\OpenSSL-Win64\bin
Extract private key with password (encrypted) -
.\openssl pkcs12 -in certificate.pfx -nocerts -out privatekey.pem
OR
Extract private key without password (unencrypted) -
.\openssl rsa -in privatekey.pem -out privatekey-nopass.pem
Extract certificate -
.\openssl pkcs12 -in certificate.pfx -clcerts -nokeys -out certificate.pem
Combine Certificate and Private key (if required) -
Get-Content privatekey_unencrypted.pem, certificate.pem | Set-Content fullcertificate.pem