SPF record entries

We received an email explaining the following:Your current DNS record should contain an entry for Sendgrid (e.g., “include:sendgrid.net”).

• Before end of day on September 25, in preparation for our email vendor consolidation, you will need to add: “+include:outboundmail.blackbaud.net ~all” to your DNS record.
• Your DNS record should contain both the blackbaud.net and sendgrid.net entries until September 27.
• After September 26, if you have not added “+include:outboundmail.blackbaud.net ~all” to your DNS, your emails may not send as expected as mailbox providers may not recognize them as “legitimate” emails.
• After September 27, Blackbaud will no longer require the sendgrid.net SPF entry. If you do not use Sendgrid for other email applications, your organization should be able to remove the sendgrid.net SPF entry from your DNS record. Please consult with your IT staff before taking this action.

I can't for the life of me figure out where to find this section to make sure those addresses are entered. Can anybody shine more light on this?