@hrdpgajjar :
Here is a file that does what you asked. I added a confirmation message if deleting records for safety reasons. You can search in the Farmer form like you did before but you just hit the Enter key instead of clicking a button. The subform attached to the Dispatch form will find Farmer and Dispatch information by selecting the record you want to display and then click the button. It does not filter the data, it simply finds it.
You are welcome to use it as you wish. Make sure each Farmer, Area, Order and Dispatch record is accurate. The Freight Charge on the Invoice form is a calculated value now based upon the standard freight rate for each transporter and the distance the planting area is. You need to complete these values.