SharePoint Online: How to Convert Classic Sites to Modern Sites?

Requirement: Convert SharePoint Online site from classic to modern

How to change classic site to modern in SharePoint Online?
SharePoint Modern experience has many advantages compared with classic, like better user experience, faster page loading, responsive design, etc. There are several methods available to switch from classic to modern experience in SharePoint Online:

Option 1: Connect SharePoint Online Classic Site to Office 365 Group
We can convert SharePoint Online from classic to modern by connecting it to Office 365 group. Here is how:

• Navigate to your SharePoint Online classic site >> Click on Settings gear >> Choose "Connect to a new Office 365 Group" from the settings menu.
  
• This invokes a wizard to connect team site to Office 365 group. Click on "Let's get Started" button.
  
  
• You'll be presented with New O365 Group properties page. You can update the group name and email alias, and select the group's privacy and then click on "Connect Group"
  
• In the "Add and assign people" page, SharePoint automatically adds owners and members, based on your existing site. You can add new owners and members, or remove people from the proposed.
  
• Click Finish when you're done.

This wizard change site from classic to modern, copies the "Home.aspx" to "Home(1).aspx", converts it to modern page and sets it as Home page. You may have to rename it - to make it neat! Connecting team sites to Office 365 group using PowerShell is explained in my other article: How to Connect SharePoint Site to Office 365 Group?


Option 2: Use PowerShell script to upgrade sharepoint online classic site to modern
Here is my other PowerShell script to convert classic team site to modern: SharePoint Online: Change site from classic to modern