You can allow your users to see and try any of the features that become available as a preview. Because these features are a preview and not general availability, they may not meet the service level requirements and may not be supported if you need tech support.
Learn more here: https://support.office.com/en-us/article/Enable-or-disable-preview-features-in-SharePoint-88c69842-7eba-4372-953f-e4cff5818b88?ui=en-US&rs=en-US&ad=US. This is an all or nothing setting, unlike the setting in Office 365 admin center that allows you to set a certain subset of people to be able to see and use preview features. Use with caution.
