When you log on to https://app.mypaymash.com/, you will find all the sales, invoices, and offers you have made so far under Sales. With each invoice you can
resend by mail
copy (is then unpaid and can be edited again)
export as PDF
With the search field in the upper right corner, you can search for the name of the customer, the employee, the invoice number, or the amount.
With the filter function, you can filter by other criteria such as the time span.
On the cash register app, under "Invoices", you can find the sales of the last 3/7/14 days (depending on the specified settings).