How to edit an existing text box? Steven Chan July 19, 2017 11:22 Updated Follow Tap and hold above the text box. Select the Edit option in the pop-up menu. Related articles How to type with keyboard? How to change text box font/background/border color? How to remove text box border? How to select PDF text? I cannot select PDF text with the lasso tool. Contact Support How to change the handwriting recognition language for an existing document?