How do I add bcc: to email header?

Babalu_MB wrote:

I have a new laptop and just noticed there is no bcc in the header and want to use it on an e-mail. How do I add to the format?

If the field isn’t listed, click the Header Fields button in the toolbar of the message window, then choose Bcc Address Field.

ref: Address emails in Mail on Mac - Apple Support

Babalu_MB wrote:

I have a new laptop and just noticed there is no bcc in the header and want to use it on an e-mail. How do I add to the format?

Try this:

In the New Message window, click the drop-down arrow located to the left of the Subject field, the BCC Address Field should appear.