Excel formula that compares thousands of cells between two sheets

Hello. I have a file that has thousands of inventory and each row is sorted by my item ID (call this file "File1"). I have another file that has the product quantities (call this file "File2"). I want to add a column to File1 that brings in quantities for each item ID that is in File2. If I had the exact same item IDs and order in both files, I would simply do an equals for the quantity cell in File2 and drag it down in File1. However, in File2 the item IDs are not in the same cells (example: item ID 1001 in File1 is in cell A5, but in File2 item ID 1001 is in cell A10). Is there a way that I can create a formula similar to an IF THEN that will check the item ID in column A of File1 and if it equals any item ID in column A of File2, it will put the quantity of that corresponding row into File1?

I know that is hard to explain. Any help is appreciated.

Thanks.

your uploaded files will be appreciated

Here is the document. I made one sheet "File1" and one sheet "File2". I highlighted the column in File1 that I made for QTY. I want the corresponding values from column D of File2 to be in that column for QTY in File1.

Thanks.

VLOOKUP will do it

That worked! Thanks guys.