Moon Invoice allows users to duplicate any invoice using a single tap. For the same, follow the mentioned steps.

1. Click on any invoice, open it.
2. Click on more options. 
3. Click on duplicate to view options

4. The duplicate options are invoice, estimate, proforma invoice, and credit note.
5. Select the appropriate option to duplicate an invoice to any of the given formats. 
6. Clicking on the given option, the invoice will be duplicated and added to the given category. For example, clicking on the estimate will add the invoice (as a duplicate) directly to the estimates.