What do you mean by Domain Extension ? 

A domain extension, also known as a Top-level Domain (TLD) is the suffix following the domain name in a web-site address, like “.com” or “org” It categorizes websites by type location or purpose, common extension include .com (commercial), org (organization), net (network) and country-specific extension like .de (germany) or .in (India)

Purpose: 

Domain extensions help organize the internet by indicating the nature of the website or its location.

Types:

Generic TLDs (gTLDs): These are the most common, like .com, .org, and .net.

Country Code TLDs (ccTLDs): These are specific to a country or region, such as .ca (canada) or uk (united kingdom).

New Generic TLDs (gTLDs):  A newer category introduced in 2012, allowing for more diverse and specialized extensions like, photography or online.