How to hire someone to build custom widget (or custom javascript) ?

Also, is it possible that we could hire Jotform or a Freelancer to build us a custom widget (or custom javascript) to enable this? We found this custom widgets approach.

https://www.jotform.com/developers/widgets/#:~:text=After%20successful%20registration%2C%20go%20to,only%20visible%20only%20to%20you.

I would like to build a custom widget and would like to hire someone to build one for me. Can you please let me know if there are freelancers that I can hire to build this custom widget for me?

If not, what coding skills are needed to complete a widget build and how long does it take to get the widget approved, once it is built.