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

Results forspf.sfdns.net

Resolver

Location

TXT

Name	TTL	Value
spf.sfdns.net	43200	v=spf1 ip4:103.27.72.0/22 ip4:185.93.164.0/22 ip4:220.158.200.0/22 ip4:203.223.152.0/24 ip4:203.223.135.0/24 ip4:116.0.120.0/24 ip4:116.0.121.0/24 ip4:103.10.78.0/23 ip4:67.222.146.0/24 ~all