Whats the difference between content and structure folders in AEM

I am using Adobe Experience Manager (AEM) 6.3. In the basic structure, components folder contains content and structure folders. In both the folders we put components. What is the difference in both the folders?

In simple terms, Components which are responsible for rendering the skeleton or the outermost part of the page are placed in the structure folder where as components which render only parts of the page are placed in content folder. Note that this is just a best practice recommendation from Adobe, you can maintain folders with custom names as well.

In older versions of AEM, components in structure folder were placed in page folder and were called page components.

High-level flow of how structure and content components integrate in a page -

• To create a page in AEM, you'll have to select a template.
• A template is first created in /conf folder. Templates are usually backed up(sling:resourceType of the template points to structure component) by a structure component to render the initial view. Common structure components includes header, footer, body which usually contains container components like parsys or responsivegrid.
• A page is then created using the template created above and the content author uses functional components (components in content) to design the page - drag and drop from components side rail or sidekick in previous versions.