Hi there, @DDP2. Thank you for getting back here in the thread. I can help you sort this out.

Your company's registration number is one of the default information in your sales forms, It'll appear on your sales form whenever you try to Print or Export them as PDFs. To remove the registration number, we'll have to go to the Display section of the Content in your Custom form style and then uncheck the box for the registration number.

I'll outline the steps below so you can proceed to remove the registration no. on your estimate. To begin, here's how:

1. Click the Gear icon in the upper-right corner.
2. Select Custom form styles under Your Company.
3. Choose a template.
4. Press Edit below the Action column.
5. Go to the Content tab, then scroll down to the Display section and then uncheck the box for VAT registration No.
6. Click Done.

For visual reference, you can refer on the screenshot that I'll be adding below.

You'll then proceed to create your estimate. To use the template that you've created earlier, you can scroll down below in the estimate, click Customise and then select the template that you made.

Feel free to refer on the screenshot below.

In addition, I've also included this helpful article for the troubleshooting steps in case you'll bump into errors when sending sales forms:  Delivery Errors when trying to email a sales form.

I'll be here in the Community in case you need assistance performing specific tasks in QuickBooks. You can also post here again if you have any additional QuickBooks-related concerns. Rest assured, our dedicated team is always ready to help you. Thanks for choosing QuickBooks, and have a good one!