A record generally specified directly on the line, here to NameCheap example:
@ - used to point a root domain (yourdomain.tld) to the IP address:
// input ip yourdomain.tld want to jump in the browser
A Record | @ | 11.22.33.44
www - is selected when it is needed to point www.yourdomain.tld to the IP address:
// input ip www.yourdomain.tld want to jump in the browser
A Record | www | 11.22.33.44
Include a detailed description of NameCheap: