Powerapps how to choose fields that are submitted to SharePoint list

Question

I have taken over a project from someone who has left the business. It is a Microsoft PowerApp which provides users with a form interface to upload items into a SharePoint list.

The submit button in the app works and the function is "SubmitForm(formName)"

My question is how does it know which fields to submit into which column in SharePoint?

for instance if I wanted to create a textbox in the form for "First Name" how would I make the powerapp submit the contents of that textbox into firstname field?

--edit removed screenshot--

Answer 1

I think you lack knowledge of powerapps w.r.t sharepoint. Go through one of the example mentioned in docs of micro soft and you will get idea of how mapping of fields are done.

Your main concern is mapping fields.

https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/app-from-sharepoint

If you check your edit form, and click on any of your field/data card you will find settings as below. Here I have created custom column as "NumberColumn" and you can find Data properties same for your field as well.