Instructions from Google can be found here.
Here is a step-by-step guide on how to add an DMARC record for your domain:
Sign in to your domain provider's website.
Find the area where you can manage your DNS records. This will typically be in a section called "DNS Management" or "Advanced Settings."
Locate the area where you can add a new DNS record.
Select "TXT" as the type of record you want to add.
In the "Host" or "Name" field, enter "_dmarc"
In the "Value" or "Data" field, enter the following text:
v=DMARC1; p=none; rua=mailto:[email protected]
**replace getrevli.com with your website domain
For the TTL, leave the default settings.
Save the new DNS record.
*GoDaddy DMARC Record
Once you've saved your changes, it may take some time for the DMARC record to propagate across the internet.