Hello Karen,
Thank you for reaching out I understand how important it is for you to include your mobile and direct line numbers in your Outlook signature especially when you want to make communication easier for your contacts. Unfortunately when an organization enforces a company-wide signature policy it automatically populates the signature fields and restricts individual customization. This is designed to maintain consistency and compliance across all users.
As an alternative solution you can consider using third-party email signature management tools. These tools provide more flexibility and allow you to add personal details such as mobile numbers or direct lines without conflicting with company policies. They integrate with Microsoft 365 and offer advanced customization options that go beyond the default settings.
I hope this answer is helpful if you have further questions feel free to reply back
Regards,
Marcelo