A records are used to map a name to a computer's address on the Internet, and are one of the primary records used in DNS servers. The A in A record stands for Address. Simply put, an A record is used to find the address of a computer connected to the internet from a name. Whenever you visit a web site, send an email, connect to Twitter or Facebook or do almost anything on the Internet, the address you enter is a series of words connected with dots.
For example, A record points simplecloudhosting.net to the IP address 184.108.40.206.
To add and modify A records for your domain, check your dns host (domain registrar or dns hosting service)
The 'A' stands for 'address' and this is the most fundamental type of DNS record, it indicates the IP address of a given domain. For example if you pull the DNS records of google.com, the 'A' record currently returns an IP address of: 220.127.116.11. 'A' records only hold Ipv4 addresses, if the site has a Ipv6 address, it will instead use an 'AAAA' record.
Example of an A record:
The "@" here indicates that this is a record for the root domain, and the "14400" value is the TTL (Time To Live), listed in seconds. The default TTL for A records is 14400 seconds. This means that if an A record gets updated, it takes 240 minutes (14400 seconds) to take effect.
The vast majority of websites only have one A record, but it's possible to have several. Some higher profile websites will have several different A records as part of a technique called round robin load balancing, which can distribute request traffic to one of several IP addresses, each hosting identical content.