SPF stands for Sender Policy Framework. It is a TXT DNS record, which ensures mail servers will accept emails sent from your domain only if they are sent from a list of trusted servers you set up. This is important in fighting spam and email forgery.
As a Creative Web Designing customer, you can easily enable and manage SPF records for your domains in cPanel -> Email Authentication. Enabling SPF there will add the default SPF record we recommend for everyone that uses our mail services.
After you create the SPF record, you need to allow up to 72 hours for the DNS changes to apply globally and for the SPF to take effect.