Customer Protected Form and Posting my data into

I have a customer who sends me a Excel bid form that is protected and they want us to enter our price, manufacturer name, catalog number and delivery into their protected form.
The fields for us to input out information into is not protected.

Each item where we need to paste info into has a unique stock number that will appear in their worksheet and also my access file or excel worksheet will have the same stock numbers that I want to somehow use either "find" or if function to copy data from a specific field in my database or worksheet to a specific field in their worksheet.

There are approximately 300 items on this bid.

Thanks for any help you can give me.