I entered my business number when I signed up for QuickBooks and now it's showing on every invoice as 'pst MB registration number' and I cannot seem remove it

Hello ksm-construction,

It's great to learn you're using QuickBooks to manage your business. The program is designed to help you automate some of the most complex calculations involved in your accounting. I'll be glad to steer you on the right path so you can get back to doing what you love. 

In order to remove the business number from your invoices, you'd have to do this through your invoice template settings. Here's how:

1. Click the Gear icon on the top menu.
2. Choose Custom Form Styles.
3. Click Edit on the invoice.
4. Choose Content.
5. Click the Header part on the sample invoice.
6. From here, uncheck the Business number and hit Done.
7. Make sure your changes are fully saved.  

This article here does a great job at explaining more about customizing your invoices, I encourage you to check it out and let me know if you have additional questions, I'm here to assist.