Note: this can only be done by site admins.
From the Gear icon (top right), select Apply a Site Template.
Select from several options to achieve different layouts.
Custom templates can be created and will appear on the 'From Your Organization' tab. These templates control logos, colours, navigation and content, but do not control home page layout.
Instead of manually uploading a logo, changing the theme colours and setting the header options, site administrators can select a design to apply and they all get updated in one shot. So far, we have built the following site templates:
Custom Site Templates are applied to the Modern experience only and only appear for the non-group connected Team template.