Normally when you create a new Event in your calendar you'll see a shortened version of the event editor. This short event editor shows you only the basics that you need to create an event in your calendar. We do this to make it easier for you to quickly create events in your calendar. If you want to see other options for your events you have to click on the "More Options" button to see your full event editor. See the image below:
If you don't want to have to keep clicking the "More Options" button in the event editor to see the full event editor you can go to the "Customize" screen and choose to always see the full editor. Follow the steps in the image below:
Alternatively, you can click on the checkbox next to "Always show full event editor" at the bottom of the Event Editor. Once you have clicked on this checkbox it will not show in your Event Editor again. If you'd like to go back to the minimized version of the Event Editor you'll need to go to your "Customize" settings to change it. See the image below: