In section creating a doctype there is a step
Make sure the custom field is unchecked before saving. Or your doctype won’t be exported. custom DocType are DocType specific to your installation of ERPNext: they will be available in your u but are not generic enough to be use elsewhere.
but I cannot unchecked the custom field I tried to click it but still does not change to uncheck. Is it ok to leave it checked if not how can I uncheck it?