test.js

function InsertTextFrame(name) {
    TXTextControl.textFrames.addAnchored(
        { width: 3000, height: 2000 },
        TXTextControl.HorizontalAlignment.Center,
        0, // TextPosition
        TXTextControl.TextFrameInsertionMode.AboveTheText,

        (addedTextFrame) => {
            addedTextFrame.selection.setText("Signature Box");
            addedTextFrame.setBackColor("LightGrey");
            addedTextFrame.setName("txsign");
        }
    );
}