Answered by Ustadh Salman Younas
Question: Is it necessary for a person to have wudu if they want to use a Quran app on a smartphone? Does the same rule that applies to touching a mushaf apply to touching the phone while the Quran is open on the device?
Answer: assalamu `alaykum
The answer to your question has been detailed by Mufti Muhammad ibn Adam here: Qur’an Application on an iPhone: Can I Touch My iPhone Without Ablution?
Checked & Approved by Shaykh Faraz Rabbani.