You can start by watching the short video explaining how they work.
Custom Field Types
There are 6 types of custom fields:
- Text – a regular text field
- List – The most common type. See below for details.
- Linked List – See below for details
- Memo – a large text area
- Number – a field for number values
- Checkbox – a check box field
- Date – a field that accepts dates only
- User – a project user field.
- Multi List - allows you to select several values simultaneously
List Field
The Custom List Field is the most commonly used custom field with a predefined list of values to choose from. For each list field you can choose to set a default value, and whether the custom field is mandatory or not.
For example, if you are working with several browsers, you can add a custom list field that will allow you to choose from a list of browsers you support.

Below you see how this custom field is displayed inside the issue. A mandatory field will be marked by a red asterisk (*).

Below you see how this custom field is displayed inside the issue. A mandatory field will be marked by a red asterisk (*).
Linked List Field
The Linked List Field enables you to specify a set of “child-lists” with different sets of values for another list defined in the system.
For example, if you test on different browsers, you may define list of browsers, such as Firefox, Internet Explorer and Chrome, as we did in the List Field example. Then, for each browser type, you might want to define a list of available versions. IE will have versions 7, 8, 9 & 10, Firefox will have versions 5.0 and 6.0, etc.
Here we create the linked-list field for the Browser field we created earlier. Each browser type has its relevant versions.

Later, when you choose a browser from the browsers list, the "Browser Version" linked-list will show you the relevant values.

Changing the Fields’ Display Order
At the bottom of the screen, under the title “Custom Fields Display Order Customization”, you can modify the order of the fields shown when viewing details for an issue, test, or requirement, as well as for test runs and test instances. To reorder the fields, click on the relevant module (for example, issues) then simply drag and drop the fields in the desired order.