In D(omain) N(ame) S(ystem) settings CNAME refers to a domain name.
Here are some aspects of CNAME to test your knowledge:

• ‘example.com CNAME www.example.com’ is blocked by my domain provider. This does not fit with their earnings model. A / AAAA is a general way out here;
• CNAME requires slightly more search time. Security tests are more complicated. A low security risk is mentioned;
• When using A / AAAA, you may or may not inconsistently refer to IPs / servers with or without www.
• Using CNAME for www. is not compatible with the use of the proposed so-called ‘Null MX’;
• For incoming email in MX settings, ‘mail.example.com’ is more stable than ‘example.com’, because in case of relocation of the website, the email traffic is not affected. Email client Outlook also defaults with ‘mail.example.com’;
• See correct use of CNAME for DMARC for ‘rijksoverheid.nl’ on https://dnsspy.io.