It depends on what kind of website you want to create. There are many scripts out there for free or for a fee.
To create a forum you can use software such as V bulletin or mybb or many of the other forum scripts out there.
To create a blog I recommend using wordpress software it powers many of the blogs that you might have visited and works great.
To create an online store many web hosts have scripts that you can install for free with a few clicks of the mouse. This goes for many other scripts as well.
Shopify is also good for creating an online stores.