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

Results forspf1.es.net

Resolver

Location

TXT

Name	TTL	Value
spf1.es.net	3600	v=spf1 ip4:192.188.22.6 ip6:2001:400:ffff:ffff:ffff:ffff:ffff:ff25 ip4:198.129.252.90 ip6:2001:400:210:3::3 ip4:198.124.252.166 ip6:2001:400:6440:3::3 ip4:128.3.41.0/24 ip4:131.243.228.0/25 ip4:198.128.153.18 ~all