1. How to Create a DMARC Record

Setup DMARC record on your domain. We’re going to copy a generic record that will work with any host.

First Check Your DNS With a DMARC Analyzer

2. Add data Zone Records

go to your cpanel select dns zone record after that select Add "TXT" Record check below image

DNS TXT Record

3. DMRC Value Input in text record

if you have no idea then you simple add this text record with your email id.

v=DMARC1;p=none;sp=none;adkim=s;aspf=s;pct=100;fo=0;rf=afrf;ri=86400;rua=mailto:xyz@xyz.com,mailto:xyz1@xyz.com