Custom field access in reports

Hi Team,
I need to create custom field (Sale type) in Item doctype, it will have fix values (A or B or C). Later i want to use this field in doctype (Sales invoice) to filter by data based on custom field. I tried below steps, but cannot find that field in doctype (Sales Invoice)

  1. New Custom field
  2. Doctype - item / field type- select / options = A, B, C / default value - C
  3. I can enter customer field details in doctype - item (looks fine)
  4. I cannot find same custom field in doctype - sales invoice (to filter based on

The Sales Invoice doctype does not have a direct link field for Item. To filter by items in a Sales Invoice, you need to use the child table within Sales Invoice, specifically the Sales Invoice Item table.

Noted, but i need to filter sales invoice based upon new custom field which is not listed along with other fields of child table.

Custom field you created in Item Doctype. You want to filter Sales Invoice.

First you create same custom field in the Sales Invoice also
then you are able to do filter on custom field