Set SharePoint to sync with the OneDrive sync client

Sign in to https://admin.microsoft.com as a global or SharePoint admin to open the Microsoft 365 admin center. (If you see a message that you don't have permission to access the page, you don't have Office 365 administrator permissions in your organization.)

In the left pane of the admin center, under Admin centers, select SharePoint to open the SharePoint admin center. (You might need to select Show all to see the list of admin centers.) If the classic SharePoint admin center appears, select Open it now at the top of the page to open the new SharePoint admin center.

In the left pane, select Settings, and then select classic settings page.

Make sure "OneDrive Sync Button" is set to "Show the Sync button."

To sync SharePoint files with the new client, you must also sync OneDrive files with the new client.

For "Sync Client for SharePoint," select Start the new client.

Select OK.

These changes take several hours to propagate. To check that they've propagated, go to a SharePoint Online site and select Sync. In the browser dialog box that confirms the request to open a program, the "Program" should appear as "Microsoft OneDrive" and the "Address" should start with "odopen://"