The custom field of type Text allows you to add any kind of information to your items in the form of text. Additionally, you will be able to add your text fields as a column in your table view.
You can create a custom field of type Text by going to the Fields tab your the workspace settings.
When your field is set up, hit the Add field button and it will appear in the list of all your custom fields on the left. Keep in mind that you can also change the order of the fields using drag and drop.
IMPORTANT: The order of this list affects the column order on your table view and the order of your custom fields in the item panel.
SOON: This will also determine the order of your custom fields on your item cards.