Hi Dlmm324,
I hope your week is going well so far! I believe the only way to remove it from transactions is to remove it through your tax agency. The steps would be the following:
1. Select Tax Tab from the left hand side menu
2. Select Manage Sales Tax in the top right hand corner
3. Locate your Canada Revenue Agency and select Edit Agency Settings
4. Remove your GST/HST number
5. Save and Close
This field is optional within the agency so it's not mandatory. Also, I would like to add that this method will remove it from all transactions and not just the packing slip. I hope that helps! Let me know if you have any further questions or concerns.
Kindest Regards,
Lourdes Fernandez