Inventory and Invoice Template : Broken Fields and Modifications Required

Good day, I am developing an Bar Code Inventory + invoice Template Excel sheet.
I need help in fixing some broken data/cell connection which happened due tweaking an existing Bar Code inventory sheet, and also effect some desired modifications.
Listed below are the details:
FIXING REQUIRED
1. The DESCRIPTION and PRICE Field (Column C and N of Sheet 1) not populating in the form field of ADD/UPDATE RECORDS & LOOKUP EXISTING RECORDS when the “Manage Inventory” button is pressed on scanning or inserting a Barcode data (Column A of Sheet 1)
2. The DESCRIPTION Field (Column B of Sheet 2) is not populating the Sheet 2 after an update is carried out on any of the Quantity in Sheet 1. [Sheet 2 is for logging Inventory Activities]

MODIFICATIONS
1. Searchable dropdown list to automatically populate Customer information and products (Yellow Field) on the INVOICE sheet using their name [Solved]
2. Print Preview the Invoice prior to printing using a Button
3. Print the Invoice Using a Button
4. Automatically log the Invoice and other customer parameters on PREVIOUS ORDER HISTORY Sheet upon Printing
5. Generation of PDF of the invoice using concatenated Invoice Number and Customer Name as File name to a folder in the C:\ drive of the computer
6. Ability to automatically send the PDF generated by email to the Client using the email in “F16” of the INVOICE Sheet. If PDF file does not exist, A message box should pop up to warn user that invoice for the order number and customer name does not exist.
7. A button to remove selected items quantities from stock and update the stock database, a MsgBox should Warn User “You are about to remove items and update the database, Do you want to continue?"
8. A button to reverse previously rejected/removed item (7 above) back to stock and update the database, a MsgBox should Warn User “You are about to add items and update the database, Do you want to continue?”
9. A button to clear the Invoice Template of Material data and Price [More like Reset all Field excluding Invoice Number]
10. Automatically generate a new serial invoice number based on an incremental value of the last logged invoice on pressing the NEW INVOICE Button.