I need to edit autofill data because there is a typo in my phone number.

Hi, I'm assuming that is coming from the "address autofill" feature. The following article describes the steps to edit a saved address: [[Automatically fill in your address on web forms]] If it's not there, you may need to delete the suggestion from the drop-down (type the first digit, press the down arrow key to selected the mistaken suggestion, press the Delete key or Shift+Delete). See: [[Control whether Firefox automatically fills in forms]]. Any progress so far?