Hi, Julie!
I love that you are already looking to add days. I am right there with you - I feel there is always room for one more Disney day!
To add a day to your existing
ticket, you will need to go to a Ticket Window outside the main gate of Disneyland Park. A friendly Cast Member will be happy to let you know what the additional cost will be and add on that magical day for you. Make sure to do this before using your last day of tickets.
To make the most of your 3 (or 4!) days in Disneyland Park and Disney California Adventure Park, take advantage of
Disney FASTPASS service so you can zoom through the lines. You may also want to look into
Disney MaxPass where you can make your FASTPASS selections on your smartphone using the
Disneyland app (fee per guest/per day applies when using MaxPass).
This fun video will explain how to use Disney MaxPass.
Wishing you a magical visit to the Happiest Place on Earth!
Cathy