How can I generate reports for my form?

What is the best way to generate reports that will be sortable by a field within your form?

There are different ways of generating form reports as shown below.

https://www.jotform.com/help/326-How-to-Create-Form-Reports-in-JotForm

If you need to view your reports offline or on your PC alone you can try downloading your form submissions as excel document and your can use the file and filter fields on your form using excel filtering.

https://www.jotform.com/help/44-How-to-Export-Form-Data-to-Excel

If you need to online reports you can try and setup visual report of your form submissions as shown below.

https://www.jotform.com/help/187-How-to-Create-a-Visual-Report-with-Your-Form-Submissions

With the above you can also filter your reports using different fields.

These are the two methods i would recommend you getting your reports depending on if you need online or offline reports.