Hey Mark- Thanks for reaching out! To download a copy of your invoice, please follow these steps:
1) Log into Lucidchart as the Account Owner of the account
2) Go to the Account/User Settings page
3) Select "Payment History"
4) Download the copy of the latest invoice
You can also include on your invoice:
1) A billing address
2) Company name
3) Your company tax number
4) The Lucid tax number
5) Set auto emailing of invoices to the account admin or an email of your choice.
Please let me know if you have any further questions.