because it helps you establish credibility as a business. Most people just assume that you have a website since the vast majority of businesses do, at least the vast majority of big companies do
What is a Domain
Domain names are used to identify one or more IP addresses. For example, the domain name microsoft.com represents about a dozen IP addresses. Domain names are used in URLs to identify particular Web pages. For example, in the URL http://www.pcwebopedia.com/index.html, the domain name is pcwebopedia.com
WHAT is hosting
Web hosting is the service that makes your website available to be viewed by others on the Internet. A web host provides space on its server, so that other computers around the world can access your website by means of a network or modem. There are literally thousands of web hosting services available today, ranging from free services with limited options to expensive, specialized business web hosting services. Which option you choose depends primarily on how you plan to use your website and how much you want to spend.
WHAT IS SEO
Search engine optimization is a methodology of strategies, techniques and tactics used to increase the amount of visitors to a website by obtaining a high-ranking placement in the search results page of a search engine (SERP) — including Google, Bing, Yahoo and other search engines