I write to inquire about the necessity of domain registration. What does it actually provide and is it necessary? Guidance sought
If you want to continue owning your own website then, yes, domain registration and renewal is necessary.
If you don't do it
i) you don't get to own the domain name, say, yoursite.com, so you cannot develop a site on that domain, or,
ii) if you own the domain already, and have built a site there, not renewing your ownership of that domain means somebody else could buy it, erase all the work you've done on your site, and start their own site on that domain.
I don't mean this offencively but this is a very... strange, topic.
A domain name is an address mapped to a webservers IP address. You can host a website without a domain name, people will just have to enter your IP address. I'm not sure what search engines will do about naming your website however...
There have been some famous websites that used nothing but an IP address, but you'll need a VPS or a dedicated server rather than shared hosting (You need to be able to setup and configure virtual host files in the apache2 configuration). They only got away with using an IP address however as the purpose of their existence was related to their IP. Their IP was also memorable.
If you can clarfiy on your question perhaps we can assist you some more?