How do I enter my company VAT number to reflect on all tax invoices and quotes?

Thank you for reaching out to the Community, @lea-zini-telkoms. I'm glad to help you with adding VAT numbers on your invoices in QuickBooks Online (QBO).

To begin, please enable VAT in your QBO company. Then, input the VAT Registration No. on the customer information page. Here are the steps you can follow:

1. Go to the Sales menu, then select the Customers tab.
2. Click the customer's name to open the Customer information page.
3. Input the VAT number in the VAT Registration No. field.
4. Tap Save.

I've included some screenshots for your visual reference. Please note that the names listed in the screenshots are just examples and not actual. 

After that, you can include the VAT Registration Number field in your invoice template. Here's how:

1. Go to Settings and then select Custom Form styles.
2. Click the Edit button or tap New style.
3. Choose the Content tab and click the upper part of the template.
4. Place a checkmark in the VAT Registration No. box.
5. Hit Done.

Once done, you can create an invoice and click the Print or Preview button to double-check what your invoice will look like and ensure that the field has been added.

Furthermore, you can customise invoices, quotes, and sales receipts in QuickBooks Online and send customer statements in QuickBooks Online.

If you have any other questions or concerns about managing your invoices in QBO, please let me know. I'm here to help 24/7.