How do you hide a field on a PowerApp when opening a new form? The approach below uses a single screen form instead of multiple screens for the various forms.

I started by creating a new SharePoint list and added two text fields:
Not on New Form
On New Form
Using the customize form option, I entered the Power App designer.

When the PowerApp designer opens, it will look like this:

To help see what’s going on with the form mode, add a text label to the form and set its Text property to: "Form Mode: " & Text(SharePointForm1.Mode)

Select the field (Data Card) that should not appear on the new item form, then select the Visible property. For the Visible property, enter the following: If(SharePointForm1.Mode = 1, false, true) . If your SharePointForm1 is named something else, use it instead of the value I presented.

Breaking down the formula a little: If the SharePoint form mode is equal to 1, visible should be false, else true.

Save and publish the app, then check if it’s functional as planned.

New item form with Form Mode: 1

Display item form with Form Mode: 2

Edit item form with Form Mode: 0