I'm going to assume the Google contacts app here since you don't tell us what you're using.
Slide in the menu from the left, tap Settings. Tap Name Format and adjust. If you also wish for it to sort by the last name, tap Sort By and adjust.
If you need additional help or have more questions or details to share, please join the site so you can reply in this thread. See
this link for instructions on how to join Android Central.