dkim - what adds the private key

I found these two support items on dkim:
https://support.everleap.com/kb/a1603/email-authentication-through-spf-and-dkim.aspx
https://support.everleap.com/kb/a1402/how-to-setup-dkim.aspx

noob question:

if using the everleap smtp server to send email, does dkim require special setup on the email sending program?

or does the smtp server create the private key and add it to the email as it passes by?

Thank you,
Layla

 

thank you for your response!

yes, that is exactly how it worked.

I was confused with 3rd party email servers ( a use case I am not using ). For 1st party stuff, it is seamless and automatic.

 

I believe the email server creates the private key and adds it to the email header and if using the everleap smtp server to send email, does dkim record require special setup on the email sending program.