You can create a new invoice for the existing job, saving you more time.
1. Select the "Jobs" module from the top-left hamburger icon. 
2. Select the job, and from the Job details page, choose the "Kebab" icon from the top-right corner.
3. Select the "Quotes / Invoices" option.
4. Select the "Add" button next to the Invoices to create an invoice based on the existing Job.
5. All the customer details and job details were pre-filled based on the Job selected.
4.
Other than pre-filled details, select/ add the necessary details.
Finally, select the "Create" button to create the quote.
With this, Invoices make a record of all the business sales, and thus it helps to keep the accounts. In addition, invoices give an overview of the business financial archive.