Dear Olivia,
Thank you for reaching out and for trying different solutions to enable the strikethrough shortcut in New Outlook. We appreciate your efforts in troubleshooting this issue.
Currently, New Outlook does not have a dedicated keyboard shortcut for applying strikethrough formatting. However, you can still use the Format Text tab in the ribbon to manually apply strikethrough to selected text.
- In new Outlook, when composing an email message or reply, select the text to cross out.
- Select the Format text tab on the ribbon, then select Strikethrough.
We value your feedback and encourage you to submit a feature request through the Microsoft Feedback Hub or Outlook’s built-in feedback option. Your input helps us improve the experience for all users.
Please let us know if you need further clarification or assistance. We appreciate your patience and look forward to assisting you further.
Best Regards,
Chris-DKN - MSFT | Microsoft Community Support Specialist.