What forms you need depends on 2 things: Your age and what you want to change.
If you are 17 or older, you need Forms for Adults. If you are under 17, you need Forms for Minors.
Forms for Adults
Adult Name and Gender Marker Packet
Adult Name Change Only Packet
Adult Gender Marker Only Packet
If you have been convicted of a felony, get the Adult Name and Gender Marker Packet with Conviction Packet
Forms for Minors
Get the Minor Name Change Only Packet