How does one add a customers Purchase Order number to an invoice? I go straight to invoice and dont make use of the quote and delivery note options. Thanks

You've come to the right place for answers, @garyjhogg-hotmai. I hope you're good and well today.

I'll ensure that you can add a purchase order (PO) number to your invoice in QuickBooks Online (QBO). This way, you can easily track them anytime. 

Let's create a custom field for PO number to achieve your goal. I'm happy to provide the detailed steps on this. 

1. Go to the Gear icon, then choose the Custom fields. 
2. Click the Add custom field button. 
3. Enter PO Number in the field and check the box beside All Sales forms
4. Turn on the radio button in Print on form (optional). 
5. Hit Save.

For more information, check out this link: How to add custom fields to sales forms and purchase orders.

After that, open the invoice and enter the desired PO number in the field. See the sample screenshot below for your reference.

In addition, see these articles below about how to copy purchase orders to quote and customise sales forms:

• Copy a quote to a purchase order
• Customise invoices, quotes, and sales receipts in QuickBooks Online

I'm always here to listen and help if you have other QuickBooks concerns. Just post a reply below. Keep safe, garyjhogg-hotmai.

thanks you have been of of great help.

I am using Simple Start QBO. So I cannot add the order no box. Do I now have to upgrade to Essentials to get the facility to make the changes to my invoice??.

Yes, you can upgrade from Simple start to Essentials, willem1.

Adding custom fields on invoices is available in QuickBooks Online Essentials, Plus, and Advanced versions. I recommend upgrading your plan if you want to take advantage of this feature. I'll show you how.

1. Sign to QuickBooks Online as primary or company admin.
2. Go to Settings ⚙, then Account and settings.
3. Select the Billing & Subscription tab.
4. Ensure your payment info is current.
5. In the QuickBooks Online section, click Upgrade your plan.
6. Review the available plans and then select Choose plan.
7. Follow the on-screen steps to upgrade your plan.

Once done, you can follow the steps outlined by my colleague above to add or create a custom field on your invoice.

Financial reports provide you with insights into several aspects of your company. The majority of reports are available for all QuickBooks Online users. I've added this article for more details: Reports included in your QuickBooks Online subscription.

Feel free to post again if you have further questions about the custom field. We're always here to help you.