The following page shows how to create an invoice from the client list using invoicefu. Foremost, you need to sign in the application. Once logged, click the 'CLIENTS' button of the header menu to access your client's list. By clicking the invoice icon shown below, you'll be redirected to the invoice creation page. The new invoice will already be filled with the concerned client data. Feel free to add any content to the invoice. To then create the invoice, click on the 'Create Invoice' button located at the bottom right corner of the formulary.
Note: the invoice icon is also accessible from the client detailed view.