Can I add my company registration number and iban details on my invoices?

Welcome to the Community, @embalmingservice.

I assure you that adding your company registration number and IBAN details to your invoices in QuickBooks Online (QBO) is possible. 

You can add those by personalizing invoice form style in your Custom Form Styles. Let me guide you on how:

1. Sign into your QBO Account.
2. At the upper right corner, click on the Gear Icon ⚙, then select Custom Form Styles.
3. Choose the Content tab.
4. Click the pencil icon on the right to edit each section on the sample form. 

• To add your company registration number details. Go to the Header section. Tap on the + Company registration number, then mark checked the box.
• To add your IBAN details. Go to the footer section. Type your details in the Your payment details.

5. Once you’ve finished editing, click Done. 

Know that applying your IBAN details is only applicable using the Airy New template. You can change your template by going to Design and clicking Change up the template.

You can gain more information on adding your bank details by checking this article: Adding bank details to your invoices.

After sending out invoices to your customers, you’ll need to record payments in QBO to have a balance account.

Let me know if you have further inquiries about your invoices and other forms by hitting the Reply button and leaving a comment. I’m just a post away. Have a good one!