If you don't use a custom URL (and the URL used for Office 365 ends in ), SPF has already been set up for you in the Office 365 service. GoDaddy, Bluehost, web.com) & ask for help with DNS configuration of SPF (and any other email authentication method).
If you are a small business, or are unfamiliar with IP addresses or DNS configuration, call your Internet domain registrar (ex.
