Timestamp Last Change of Row

For a column 3 or C, we want to timestamp anytime the row changes.

Code.gs

function onEdit(edit) {
var row =  edit.range.getRow()
var timestampTimeZone = "GMT-5"
var timestampFormat = "yyyy-MM-dd'T'HH:mm:ss"
if( row >=2 ){
  var timestamp = Utilities.formatDate(
    new Date(),
    timestampTimeZone,
    timestampFormat)
  SpreadsheetApp
    .getActiveSheet()
    .getRange(row,3,1,1)
    .setValue(timestamp)
}
}