You can carry the following info to a form: Product Name, Quantity, Label Info, Batch Number, Expiry, Invoice Date, User Dispensing the Product. To do this you must add the following text into a form: [product_service] [quantity] [label] [batch_number][expiry_date] [invoice_date] [user_name]
The product must then have a 'special action' for form printing assosciated with it (exactly like the vaccination reminders work - check how your vaccines are set up in the inventory).
When you dispense the product it will then have a [form] link next to it. Clicking this link will print the appropriate form and carry through the batch numbers and other info - it will replace the [batch_number] statement with the correct batch number.
If you want to input your own info, try using [user_input] or [user_textarea] on the form.