A (Address) Record

Forward Lookup Zone
IPv4 : A Record
IPv6 : AAAA Record

CNAME (Canonical Name) Record

Used to resolve a Domain Name to another domain name
Causes DNS Lookup to be performed for the Alias Domains IP Address
Can be used to redirect to another server

MX (Mail Exchanger) Record

Points domains to Mail Servers
MX records like CNAME records always point to another domain
Generally a server will have multiple MX records and each one has a priority
The MX record with the lowest priority number is the Primary Server

SOA (Start of Authority) Record

Stores administrative details about a Zone
Contains information like Owner, TTL, Authoritative Server, Serial Number

NS (Name Server) Record

Points to other DNS Server
NS records are also generally configured in pairs (Primary and Secondary)

SRV (Service Location) Record

SRV points to a service that are running on the network
The record also contains the port number to find the service

PTR (Pointer) Record

Reverse Lookup Zone
Have an IP Address need Name
Used by Mail Services to check if the mail is Spam

TXT (Text) Record

Custom DNS record to associate an Service with a specific DNS Zone
Used to verify the ownership of an domain
Office 365 requires an TXT record to confirm organization owns a specific Domain