It is, of course, important that every invoice has an invoice number.
But how do you set this up in MICE?
Step 1: Go to Setup (via the main menu).
Step 2: Select Billing (at the setup menu, below settings).
Step 3: Scroll down to the heading 'Invoicing identifier template'.
Here you can set the invoice number. It states how the year can be processed.
(Y) -> whole year 2026
(y) -> abbreviated year 26
On the right you will then see the next invoice number.
Note that when you create your first invoice number half way through the year that you start with the number where you left off. As an example when your last invoice number ended at 20 in the year 2026:
[y]0020 = 260020