Dawud ibn Yazid asked Abu Al-Hasan al-Thalith عليه السلام (the Third), peace be upon him, about paper (qaratis) and parchment (kawaghidh) that have writing on them, whether it is permissible to prostrate upon them. So He عليه السلام wrote: “It is permissible.”
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 2, p. 252