With this article, we will discuss what SPF does and what it does not: Does: SPF authenticates the sending server of the email based on the sending IPv4/IPv6 address. SPF focuses on a header that is not visible to the end-user (Return-Path, MAIL ...
The company's domain will be configured through SPF, DKIM and DMARC records. The third-party vendor will obviously use that domain to send marketing emails.