PDF tickets are accessible via your order details page and may or may not require printing (the PDF would explicitly say whether or not printing is required, but we always recommend doing so anyway just in case).
What if I don't have a printer to print my PDF tickets as required?
Options such as your local library, FedEx, UPS print and ship center, or friends and family are all good resources to obtain access to a printer. You can always download and save the PDF files and send them as an attachment via email to another party to have them print for you, if needed.