It can be anything! An apex, subdomain, or even a URL.

Results forspf2.septacode.com

Resolver

Location

TXT

Name	TTL	Value
spf2.septacode.com	1800	v=spf1 ip4:166.78.68.0/22 ip4:167.89.0.0/17 ip4:168.245.0.0/17 ip4:185.189.236.0/22 ip4:185.211.120.0/22 ip4:185.250.236.0/22 ip4:192.237.158.0/23 ip4:192.254.112.0/20 ip4:198.21.0.0/21 ip4:198.244.48.0/20 include:spf3.septacode.com ~all