How should an SPF record look like?
An SPF record is a Sender Policy Framework record. It’s used to indicate to mail exchanges which hosts are authorized to send mail for a domain.
Sender Policy Framework records should follow specific syntax guidelines. In some cases your email provider may generate a ready-to-use string for you, but you can customize it yourself. You can use a third-party SPF Wizard
or any other online tool to simplify the task.