Labels can only be generated if a seating plan is available. If you have set up an event with a seating plan, then edit it and click on the "Categories, seating plan" section under "Tickets & seating plan". The "Print seat labels" button is located directly above the seating plan. If you click on this, you can select which label format you prefer. The appropriate PDF is then generated via "Print seat labels", which you can download and print after inserting the appropriate label sheets.
The ticket category, seat number and ticket ID are printed on the labels. The names of the ticket purchasers are not printed. If you issue personalised tickets (e.g. with the purchaser's name and company), these fields will only be printed on the ticket.