In order to pass SPF validation with Amazon SES you can either leave the default MAIL FROM address that Amazon uses or setup a custom MAIL FROM domain so that it can align with the FROM address in case you plan to use DMARC.
In the first case you do not have to do anything as Amazon already uses their default MAIL FROM address and SPF passes.
If, however, you would like to use your own MAIL FROM domain and have DMARC validate against SPF please click on the button below for the steps needed to create a custom domain.
NOTE: If you would like to be DMARC compliant with Amazon SES you must use relaxed alignment which is the default.
As a side note the SPF mechanism used to authorize Amazon SES to send emails on your behalf is: