How To generate SPF and DKIM record in Unix Server

Hi Team

I have one domain called example.com where i need to update SPF and DKIM record type in DNS Zone file for this particular domain.

Please let us know how can we generate this SPF and DKIM for one this domain.

Is there any third party vendor for this to generate SPF and DKIM.

Regards
Arunk

What is your OS? and do you use control panel like cPanel/WHM or so?