How do I add a list of work undertaken on an invoice, I can only type in one continuous line?.

It's great to see you around the Community, @emma-ward91-yaho.

Are you referring to product and service within an invoice view? If so, we'll work in this together and here’s how to do it:

1. From the menu, choose Invoices, then Create Invoice.
2. Choose an existing customer or input their name, address, and email address to create a new one.
3. Set the due date in the Due Date area to the date you want to be paid by.
4. To add things or services you sold, click Add product & service. Give the service a name and a description.
5. From the dropdown menu, choose Flat Rate or By Hour. If you're charging for a product, choose By item. Enter a dollar amount. Then choose Add to invoice from the drop-down menu.
6. Select Add work to add more items to the invoice.
7. Select Send invoice when you're ready to email your invoice. To see what your consumer will receive, select the arrow and Preview.

Moreover, I’ve got this article to guide you more regarding invoices in QuickBooks Self-Employed. In this link, steps are also provided here on how to turn on payments so that consumers can make electronic payments on their invoices.

 
 Additionally, here are other articles for you that might help you in the future about (QBSE):

• Turn on tags in QuickBooks Self-Employed.
• Automatically track mileage in QuickBooks Self-Employed.
• QuickBooks Self-Employed Overview.

If you are referring to something else just drop a comment below. I am always here to lend a helping hand. Keep safe.