Every website that you visit consists of a domain name and a web host. The easiest way to picture it is to think of the domain name as the address and the hosting as the physical building.
When you are browsing the web and you type in a URL (i.e. https://www.wiss.pk), your web browser basically queries that domain name (i.e. wiss.pk) and asks it where the website is hosted. The browser then loads up the contents that are stored there.
Hosting is effectively the process of using a server to host a website, and there are all sorts of different types of hosting available out there on the market. WISS, just like most web hosts offers different packages so that their customers can pay for just the resources that they need. The more popular the website is, the more resources it's likely to need to function effectively.
The good news is that with WISS, you can scale your hosting package as and when you need it, so you can start off with Single hosting plan and gradually upgrade to Business or even VPS plan later.