In this article, I have explained navigational types and structure in SharePoint.
– Global and current navigation
– Structured navigation
– Managed Navigation
Global and current navigation has been described as inverted ‘L’
Global navigation look likes below screen
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Structured Navigation:
Structure navigation it automatically generates the link when the pages, list and libraries and subsite has been created and also manually add links under navigation options.
Following images show structure navigation:
Navigate to site settings -> Under look and feel -> Click Navigation
Choose the structural navigation option for Global navigation and also check the show subsite it will help to display the child nodes under parent node

If you need structural navigation for current navigation also it’s your choice
Also you can create navigation links manually by Click Add heading


Navigation terms in sharepoint online></div><div><br></div><div> </div><div>Click Ok</div><div>So now the link has been visible in a page</div><div><br></div><div style=Navigation terms in sharepoint 2016
Managed Navigation:
Managed navigation it does not automatically create a navigation links like structured navigation. It allow the user to create a site navigation term sets (metadata) using term store management tool under site navigation option.
Following images show Managed navigation:
Navigate to site settings -> Under look and feel -> Click Navigation
Choose the Managed navigation option for Global navigation.

Under managed navigation term set
Click create term set

Open the term store management tool for creating navigation term and term sets

Click Ok

Read some SharePoint tutorials below:
- Configure Add-In or app development environment in SharePoint server 2016
- Communication Site Overview in SharePoint online Office 365
- SharePoint Online communication site Hero webpart
- Change the SharePoint List View into JQuery News Ticker Using JS Link CSR
- Promoted links web part in SharePoint online
- How to create and configure metadata navigation and filtering SharePoint Online?
So now the navigation has been work perfect. For UI and responsive visit, the below article.
Create a responsive navigation menu using managed metadata navigation in SharePoint server 2013
Happy learning!