Making the amount box larger on Authorize.net integration

I am picking up the amount of sale as user defined. But I noticed I need a larger box for the amount. How do I make the box longer, add "$", and comma?

May we know if you're referring to this form https://www.jotform.com/91425714001950?

I can't seem to find any payment integration in that form.

To clarify, do you want to edit the pricing field?

Usually the Form Calculation widget would work in adding the dollar sign and comma to the calculation. 

Here are the steps.

You may use the Form Calculation widget to add the dollar sign and comma to the calculation.

Just add the dollar sign to the Form Calculation and click on (...) to open the widget settings.

Then go to Options and enable "Use commas for decimal point".

Looking forward for your response.