Hi, 
Refer the app:
https://apps.odoo.com/apps/modules/16.0/one2many_search_widget/

Generally when you enter the product in the sale order line, it puts 'name' of the product in the 'name' field of sale order line, that field is labelled as "description".

Now there are two options

1./ You can add the field "order_line" in the search view and then type in the product name, so system tries to search in the 'name' field of the order line and if it is found there, it will list out those sales orders.

2./ You can directly use the 'advanced search' option in the search view of sales order and on the Order Lines 'contains' operator you can type in the product name and search it, which will list those sales orders with that product.

Hope this helps. !!

Thanks. The advanced search is working good if I am giving the product name. But if I want to search with other fields like qunatity. Then the advanced search is not working. I want to search with the remaining fields also.