Show/hide SharePoint list column in New/Edit form Using Powershell script
First get the website URL, list name and column objects
$webUrl = Get-SPWeb http://dev-pc/sites/dc
$listName = $web.Lists["Projects"]
$columnName = $list.Fields["Project Description"]
If you want to hide the column from Edit Form then Change the ShowInEditForm property and update objects
$columnName.ShowInEditForm = $false
If you want to hide the column from New Form then Change the ShowInNewForm property and update objects
$columnName.ShowInNewForm=$false
$columnName.Update()
$listName.Update()
$webUrl.Dispose()
Please change the WebUrl, list name and column name values as per your environment. To show the column just replace the $false values to $true.