DomainKeys Identified Mail (DKIM) standard is designed to help prevent spoofing on outgoing messages sent from your domain.
Email spoofing is when email content is changed to make the message appear from someone or somewhere other than the actual source. Spoofing is a common unauthorized use of email, so some email servers require DKIM to prevent email spoofing.
DKIM adds an encrypted signature to the header of all outgoing messages. Email servers that get signed messages use DKIM to decrypt the message header, and verify the message was not changed after it was sent.
Follow the following steps to setup DKIM on GSuite.
Go to google admin console -> apps -> google workspace -> gmail -> Authenticate email -> generate new record -> choose 1024 DKIM bit length -> copy generated domain key -> go to cpanel -> advanced DNS zone editor -> enter the domain key as a text record -> go back to google admin console -> click Start authentication button -> DONE.