Explain the importance of domain name?

Domain name although the Age of Domain matters, search engines do not favor older and established sites with no recently updated content, it is better to have the content separated and have a different domain (preferably with the keywords in it) for different niches

Domain name is online identity for a website and each website has it's unique name that is called as domain name, domain name provides online identity for a business or website. If you want to access your business online then you must need a website.