Lynx handles all invoice functions in "batches". This is to insure the accuracy of data entry (especially money amounts) into the system, All batches are entered by "type". For instance, deliveries are entered separately from service invoices. You'll notice that the system is organized by these separate "types". Separating the system like this allows for very specific handling of each transaction type. This helps to optimize the data entry function and speeds up your work.
The system can be configured to meet your specific needs and operating style. For instance, you can set "Preferences" that tell the system how you want to operate.
There are no particular time-constraints built into the system. You can enter what you want whenever you want and close periods whenever it's convenient. Of course, there are common sense limitations to this like closing at the end of the month and not getting too far behind with the transactions that need to be entered into the system.
The Invoicing window is laid out in a "Tab Style", with tabs for the "Batch", "Invoices", and "Invoice Detail"