Based on your business requirements you may want to capture custom information in addition to the standard fields. Usually each type of project you do will have a standard list of custom fields you need to capture. Thus you can define custom fields for each project category. The custom fields for a project collectively are referred to as the "Custom Form".
The custom form is automatically displayed on the "Add Project" form depending on the project category selected.
You can add text boxes, drop-down lists, check boxes, multi-select lists or file attachments.
Fields can be marked mandatory. This is enforced while creating a project.
Custom fields are searchable i.e projects can be located by searching for data entered into these fields.
If custom fields are modified, previously created projects will continue to have the old fields and data.