The Projects database comes with multiple custom fields that can be modified by you to include different type of information. When you double-click on a custom field label, you will get a popup like this to provide your options.
The Field Label text can be used not just to remember what you are using the field for, but also to enforce data restrictions on a field. Using special characters such as $, #, % or the word "date", all have their own effects as you can see from the screen shot above.
The Edit Input Type has a particular choice, Drop Down List, that will force anyone doing data entry to only select something from a list you make here. They will not be able to enter anything other than the specific choices listed on the right side of the screen under Drop Down List Items.
If your field label includes a $ or # character to make it a financial or numeric field, you can choose to have a sum or average displayed at the bottom of the main Projects screen if this column is visible there.
This help article applies to Time & Chaos 7