Hi @clarkej , thanks for the reply,
There is no direct link between sales invoice and phone and customer and phone , i.e there is no field like phone number field in sales/customer doctypes.
but there is one in Contact_person and in sales invoice i found that there is search by contact person (i had completely missed that).
so you can search contact person by phone after i set it in contact doctype and get the invoices from contact person.