Mailboxes: SPF Record
Without SPF, messages sent from your organization or domain are more likely to be marked as spam by receiving mail servers.
SPF helps protect your domain against spoofing and helps prevent your outgoing messages from being marked as spam by receiving servers. SPF specifies the mail servers that are allowed to send emails for your domain. Receiving mail servers use SPF to verify that incoming messages that appear to come from your domain were sent by servers authorized by you.
For Google Workspace Users:
Adding it to Wix Domains - DNS Settings
To set up SPF for your domain, add a DNS text (TXT) record in your domain provider's management console. TXT records are a type of DNS record that has information for servers and other sources outside your domain.