You can easily add new fields for the following entities: Project, Contract, Customer & Empowerment.
In order to add a new field, just go to Settings / System / Custom Fields (or click here).
You'll see a complete list of fields, per entity. To add one, just click the Add button and fill in the required data.
There are three field type currently available:
Text - just a simple text, like a Name or Address
Options - creates a dropdown with these options; Options must be comma separated
Number
Once created, these fields are available in the related screens (Contract, Customer, Project, etc)