How to enable/disable the automatic SharePoint news digest
The new SharePoint news digest uses a built-in intelligent ranking so that the users see the most relevant content to them if they have missed something published in SharePoint.
The email is sent on a weekly basis and if your organization is already branded the email will pick the colors and the logo automatically from it. Despite the weekly cadence the users will not receive an email if there is nothing relevant/published to show in a particular week.
How to disable the automatic SharePoint news digest
This feature will be enabled by default in your tenant but if needed you can turn it off by using the following PowerShell script:
Connect-SPOService -url https://contoso-admin.sharepoint.com Set-SPOTenant -EnableAutoNewsDigest $false
Once theses cmdlets get executed all your users will stop receiving the weekly news digest.
Despite getting the automatic digest disabled you will be able to continue to generate custom digest from the news site available in all site collections, in this link you can find detailed instructions about how you can do it.
How to enable the automatic SharePoint news digest
If later on you decide to enable the news digest again you can do it by running the following PowerShell cmdlets.
Connect-SPOService -url https://contoso-admin.sharepoint.com Set-SPOTenant -EnableAutoNewsDigest $true
Once theses cmdlets get executed all your users will start receiving the weekly news digest if there is something relevant posted for them. In the following image form Microsoft you can see how the automatic digest with the organization branding looks like.