SharePoint is the content management system provided by Georgia Tech's campus Office365 subscription. You can access SharePoint by logging into Office 365, then selecting the icon in the upper-right-hand corner, often described as the 'waffle' icon.
Public websites through SharePoint are no longer available, as Microsoft has discontinued this service. You can still use SharePoint to create internal information sites (AKA intranet sites), but you can only make them available at most to all Georgia Tech Office 365 users (not the general public). And, in most cases, you'll want to look at Microsoft Teams, which is an eventual replacement for SharePoint and utilizes a lot of SharePoint functions and features while providing a better interface and new features of its own.
Help and documentation about SharePoint can be found inside the application itself, and also in the OIT Frequently Asked Questions site.