You need administrator rights in Jira to perform the tasks on this page.
Custom fields are typically configured on the Custom fields page. This page contains numerous links that enable you to further customize the behavior and appearance of your checklists by:
https://okapya.atlassian.net/wiki/spaces/CHKDOC5/pages/1966145581/Creating%2C+editing+or+deleting+configuration+scheme+contexts: Modify the configuration scheme context and choose the issue types and projects to which the configuration scheme will apply.
https://okapya.atlassian.net/wiki/spaces/CHKDOC5/pages/1966145588/Editing+global+items: Create, edit, delete or disable global checklist items and headers.
https://okapya.atlassian.net/wiki/spaces/CHKDOC5/pages/1966178352/Editing+default+local+items: Create, edit or delete default local checklist items and headers.
https://okapya.atlassian.net/wiki/spaces/CHKDOC5/pages/1966112870/Editing+parameters: Customize the various checklist settings.
https://okapya.atlassian.net/wiki/spaces/CHKDOC5/pages/1966080093/Editing+statuses: Configure the statuses that can be assigned to checklist items.
For more information about custom fields, see the Atlassian Jira documentation.
To access the Custom fields page:
Go to Administration > Issues.
In the sidebar, go to Fields > Custom fields.
In the Actions column, click the menu icon for a specific custom field and click Configure.