Create a form from spreadsheet where my customers can enter data and get a price

I'm afraid passing the data from the form to a spreadsheet and back isn't possible.

However, you can create a form that will take the parameters and calculate a price.

For example:

https://form.jotform.com/73135523251953

You can then export this information to a spreadsheet:

1. Google Sheets

How to Integrate Form with Google Spreadsheet  

2. Excel

How to Export Form Data to Excel 

And you can also take a payment if you like using a payment integration. You can use PayPal, Stripe, Authorize.net, etc. 

How to Pass a Calculation to a Payment Field   

I just want to upload an existing spreadsheet ( attached) into a form on
jot form where my customer can enter data and see the result . Is that
achievable?
...

Wait after reviewing these links this is what I need But I am not sure how
to do this. Where do I get the sample form?
...

You need to copy this URL:

https://form.jotform.com/73135523251953

And follow the instructions here:

How to Clone an Existing Form from a URL 

Then you can modify a copy as you like