PS E:\Certificates> new-selfsignedcertificate -certstorelocation cert:\localmachine\my -dnsname www.example.com -NotAfter 2100.12.31
PSParentPath: Microsoft.PowerShell.Security\Certificate::LocalMachine\my
Thumbprint Subject
---------- -------
6B56F00AA1EB7C981614072D6BBB89F292D3A0BA CN=www.example.com
PS E:\Certificates> $pwd = ConvertTo-SecureString -String "GCgcPIN**1" -Force -AsPlainText
PS E:\Certificates> Export-PfxCertificate -cert cert:\localMachine\my\6B56F00AA1EB7C981614072D6BBB89F292D3A0BA -FilePath e:\Certificates\Client.pfx -Password $pwd
Directory: E:\Certificates
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a---- 09/27/2017 10:54 2725 Client.pfx
PS E:\Certificates>