How in JSON add field with link to attribute of other doc type?

ERPNext
1

Guys help me please if you know:
How in CUSTOM.json show status from delivery note?
I want see status of current delivery note - not create new (as I did):

CUSTOM.json:

   {
 "allow_on_submit": 0,
 "bold": 1,
 "collapsible": 0,
 "description": "Indicates that the shipment note is a part of this delivery ",
 "fieldname": "delivery_note",
 "fieldtype": "Link",
 "hidden": 0,
 "ignore_user_permissions": 0,
 "ignore_xss_filter": 0,
 "in_filter": 0,
 "in_list_view": 1,
 "label": "Delivery Note:",
 "length": 0,
 "no_copy": 0,
 "options": "Delivery Note",
 "permlevel": 0,
 "print_hide": 0,
 "print_hide_if_no_value": 0,
 "read_only": 0,
 "report_hide": 0,
 "reqd": 1,
 "search_index": 0,
 "set_only_once": 0,
 "unique": 0
},
   {
 "allow_on_submit": 0,
 "bold": 0,
     "collapsible": 0,
     "depends_on": "eval:doc.delivery_note",
 "default": "Draft",
 "fieldname": "status",
 "fieldtype": "Select",
 "hidden": 0,
 "ignore_user_permissions": 0,
 "ignore_xss_filter": 0,
 "in_filter": 1,
 "in_list_view": 0,
 "label": "Status",
 "length": 0,
 "no_copy": 1,
 "oldfieldname": "status",
 "oldfieldtype": "Select",
 "permlevel": 0,
 "print_hide": 1,
 "print_hide_if_no_value": 0,
 "print_width": "150px",
 "read_only": 1,
 "report_hide": 0,
 "reqd": 1,
 "search_index": 1,
 "set_only_once": 0,
 "unique": 0,
 "width": "150px"
},
2

@Katerina_Romanchuk first! I fell you are doing something wrong!

You don’t need edit any JSON file in Frappe or ERPNext.

You need edit a doctype!

To fetch a value from other doctype, you only need put a data field, as read only e.g.: dn_status with the option. delivery_note.status

Pls, take a look into this: https://frappe.github.io/frappe/user/en/tutorial/doctypes