how do I add additional lines from the time sheet to an existing invoice

Do you mean adding more billable time entries to an existing invoice, Awilda? If so, I'm delighted to guide you through the steps.

Here's how:

1. Navigate to the Sales menu, then Invoices.
2. Modify the Date field to locate the existing invoice swiftly.
3. Click the View/Edit option under the Action column.
   
4. Select the Manage button, then the Suggestions dropdown.
5. Tick Suggested transactions.
   
6. Add the appropriate time entries from the list.
7. Once done, hit Save and close.

For more information on adding billable time data to invoices, click this link: Invoice customers for project expenses in QuickBooks Online.

Nevertheless, if you mean adding more details in the time entries when attaching them to your invoices, this is not an option in QuickBooks. It's because the platform relies only on how you've tracked and entered time activities in its records.

Additionally, you can review this article to gather more insights about how your team members can manage time entries in QuickBooks: Track and submit your time using QuickBooks Time web.

Need help streamlining your financial tracking and processes? Our QuickBooks Live Expert Assisted team is here for you. They can provide professional and in-depth guidance to achieve specific bookkeeping tasks in QuickBooks.

If you have more questions about generating invoices for your billable time data, click the Reply button. We're always here to help.