There are three core record types.

The A record

An A record gives the ip address of a subdomain. You can use  "*." on the left of a subdomain to wild card all subdomains. 

examples

 The CNAME record

This record maps done name name to another. For example www.mydomain.com to mydomain.com. The problem with this is that it will involve two lookups to the nameserver to actually find the final IP address. As such CNAME records are not a great idea.

 examples

 The MX record

The MX mail exchange record directs mail to the domain/subdomain to a mail server,  When mail is sent to the domain, the mail servers will be tried in lower MX value first order. Whilt it is recommended you have a backup mail server, the reality is that this is pretty rare these days.

 examples

The TXT record

The TXT record stores character data, typically this is used to store an SPIF anti-spam record.