When you are logged in, you will see a top bar section on your website, this section is called the “Admin Bar”. Depending on where you are located on your website, the admin bar will be different if you are in the front-end or the back-end of your site.
Admin bar contains some helper links such as a link going to the admin dashboard, themes, widgets, website’s customizer, etc. It will show you some notifications like new updates and new blog post comments. Admin bar also contains a shortcut menu if you want to add new pages, blog posts, users, etc.
At the right side, you will see your username, which links to your user profile. When you hover your mouse in your username in the admin bar, you will see submenu items where you can go to edit your profile and a logout link if you want to exit your access.
There are some plugins and themes that will add new settings and helper links in your admin bar. For example, I have a plugin from Siteground called the SG Optimizer. This plugin helps my website connects to the Siteground servers and add more features like caching and optimization for additional website performance. This plugin adds a new menu item in the admin bar, which is the “Purge SG Cache”. When you click this menu item, the cache that was generated by your website will be deleted.