What the records are for
A and AAAA give the site’s IP addresses, CNAME makes a name an alias of another, MX names the servers that accept mail and NS the servers that hold the zone. TXT carries domain verification and mail policies, and CAA limits which certificate authorities may issue certificates.
SPF, DKIM and DMARC in plain words
SPF lists the servers allowed to send mail for the domain. DKIM signs every message so it cannot be altered on the way. DMARC tells the receiver what to do when those checks fail and sends you reports. Without all three, mail lands in spam more often and it is easier to forge mail in your name.
Queries run from your browser over Cloudflare DNS-over-HTTPS (1.1.1.1).