2 resources from support.microsoft.com we point founders to, and the questions each answers.
📄 Article
✓ Link checkedFreeBeginner
Microsoft's help for new and classic Outlook for Windows, Outlook on the web and Outlook.com. In new Outlook it is Settings, Accounts, Signatures; classic Outlook keeps signatures on the device.
Microsoft's own explanation of what Windows already includes at no cost: Microsoft Defender Antivirus, Windows Firewall and Smart App Control, giving real-time protection from first startup.