Drupal makes it easy to manage content. In the past, changing web content usually meant someone had to edit html. It was hard for content editors to make changes and developers were tied up with work when they could be adding features.
Content Edit Form
Content types have an edit form, which can be configured by editing the content type and clicking the Manage form display tab.
Text Formats
Text formats specify which buttons and content are allowed. They can be set up to limit html or provide advanced content features.
The default editor included with Drupal is CKEditor.
Go to Configuration > Content authoring > Text formats and editors.
Publishing Content
Content can be published, and if not it is hidden from users who are not logged in.
Content Administration
Browse and edit existing content.
To access it, click on "Content" in the admin toolbar in the top left of the page.