How can I send an email to all the employees at once ?

QuickBooks Online doesn't have a built-in feature to send mass emails or push notifications directly to all employees at once for company-wide announcements.

As a workaround, you can export your employees' email addresses from their profiles in QuickBooks to your regular email client (such as Microsoft Outlook or Gmail).

Then you can create a distribution list or add their addresses to the BCC field of an external email to send the announcement all at once.

Let us know if you have other concerns.