Is it permissible to write things other than the Quran in the Uthmani script? And is it forbidden to discard anything written in the Uthmani script?

The Uthmani script is the method by which the Qurans were written during the era of Uthman ibn Affan, may Allah be pleased with him. The preponderant opinion is that it is not permissible to write Qurans using any script other than this one. The majority of scholars hold the view that it is obligatory to write the Quran in the Uthmani script, while some permit writing it in modern orthographic scripts. The Fatwa Committee of Al-Azhar and contemporary scholars have deemed it obligatory to adhere to the traditional method of writing the Mushaf (Quran), in order to preserve the Quran in its original form, both in recitation and writing.

As for writing non-Quranic texts in the Uthmani script, if it is an entire book or a complete page such that the reader might mistake it for the Quran, then this is not permissible due to the resemblance of non-Quranic text to the Quran. However, if it involves only a few words that would not confuse the reader, such as replacing the alif with a waw in the word "الصلاة" (prayer), then there is no harm in that.

It is prescribed to protect every revered and respected name, according to Islamic law, from degradation. As for writings that have no sanctity in Islamic law, they hold no sanctity. Even if some of them are written with the Uthmani script, as long as the written content is not Quranic and does not contain the mention of Allah Almighty, there is no harm in discarding or disposing of it.