The easiest way is to use AddEvent - create your event, copy the Add to Calendar link, and paste it as a hyperlink in your Outlook email. This works whether you are sending a one-off email or building a template in Outlook.

For a one-off Outlook email

1. Create your event in AddEvent and copy the Add to Calendar link from the Sharing tab
2. In your Outlook email, type the link text (e.g. "Add to Calendar")
3. Select that text, press Ctrl+K (or right-click > Link), and paste the AddEvent URL
4. Send - recipients click the link and choose their calendar app

For Outlook email templates

Paste the AddEvent link as a hyperlink in your template. The link works for all calendar apps the recipient might use - not just Outlook.

For Outlook direct calendar links (Google only)

Outlook also lets you insert a calendar invite directly, but this only creates an Outlook/Exchange meeting request - not a universal link. It works for other Outlook/Exchange users but not for recipients on Google Calendar or Apple Calendar.

Important: Outlook safelinks

Outlook's security system wraps all links in a safelinks.protection.outlook.com redirect URL. AddEvent links are designed to work correctly through this wrapping - the redirect preserves the destination and the Add to Calendar flow completes normally.