Git is a source code versioning system that lets you locally track changes and push or pull changes from remote resources. GitLab, GitHub, and Bitbucket are just some of the services that provides remote access to Git repositories. In addition to hosting your code, the services provide additional features designed to help manage the software development lifecycle. These additional features include managing the sharing of code between different people, bug tracking, wiki space and other tools for ‘social coding’.
Using an HTTPS remote URL has some advantages: it’s easier to set up than SSH, and usually works through strict firewalls and proxies (like here in DkIT). However, it also prompts you to enter your credentials every time you pull or push a repository!