# Mapping custom fields
In Jira, each issue type, like epics, stories, tasks etc, have their own "screen" defined. A screen contains a list of fields that can be set when creating or updating the issue. If we try to update a field value that is not present on the issue's screen, Jira will throw an error.
### How to add custom fields to an issue type's screen
The easiest way to add a field to the screen of an issue type is to first click **create**:
Select the issue type you would like to add the field to and then select **Find your field**:
Type the name of the Avion field and follow the link to the screen page:
Add the Avion field at the bottom of the list:
Reopen the field finder and you should see three ticks:
