The Prophet ﷺ has a secretary named Sijill. (Using translation from Abū Dāʾūd 2935)   

فِي قَوْلِهِ تَعَالَى {يَوْمَ نَطْوِي السَّمَاءَ كَطِيِّ السِّجِلِّ لِلْكُتُبِ} [الأنبياء 104] قَالَ كَانَ لِلنَّبِيِّ ﷺ كَاتِبٌ يُدْعَى السِّجِلَّ  

The Prophet ﷺ has a secretary named Sijill. (Using translation from Abū Dāʾūd 2935)   

السِّجِلُّ كَاتِبٌ كَانَ لِلنَّبِيِّ ﷺ  

[Machine] The Prophet ﷺ received a letter from a man. He said to Abdullah ibn Arqam, "Answer it for me." So he wrote down his response and then read it to him. The Prophet ﷺ said, "You have done well and done good. O Allah, grant him success." When Umar became the leader, he would consult him.  

أَتَى النَّبِيَّ ﷺ كِتَابُ رَجُلٍ فَقَالَ لِعَبْدِ اللهِ بْنِ الْأَرْقَمِ أَجِبْ عَنِّي فَكَتَبَ جَوَابَهُ ثُمَّ قَرَأَهُ عَلَيْهِ فَقَالَ أَصَبْتَ وَأَحْسَنْتَ اللهُمَّ وَفِّقْهُ فَلَمَّا وَلِيَ عُمَرُ ؓ كَانَ يُشَاوِرُهُ  

[Machine] I asked a brother, "Who was the scribe of the Messenger of Allah ﷺ?" He said, "Abdullah ibn Arqam, and he brought us a book from Abu Bakr in Al-Qadisiyyah, and Abdullah ibn Arqam wrote in it."  

قُلْتُ لِشَقِيقٍ مَنْ كَانَ كَاتِبَ رَسُولِ اللهِ ﷺ؟ قَالَ عَبْدُ اللهِ بْنُ أَرْقَمَ وَقَدْ أَتَانَا كِتَابُ أَبِي بَكْرٍ ؓ بِالْقَادِسِيَّةِ وَفِي أَسْفَلِهِ وَكَتَبَ عَبْدُ اللهِ بْنُ أَرْقَمَ  

[Machine] The Prophet ﷺ appointed Abdullah ibn Arqam as his scribe, and Abdullah would write for him and answer for him to the kings. It was known from his honesty that he would command him to write to some of the kings, so he would write, then he would command him to write and seal, and not read it due to his trust in him. Then, he also appointed Zaid ibn Thabit as a scribe. He would write the revelations and also write to the kings. Whenever Abdullah ibn Arqam and Zaid ibn Thabit were absent or needed to write to some commanders of the armies and the kings, or write a letter to a person that Jafar ibn Abu Talib would dictate, they would write it. Omar and Uthman had written for him, and Zaid, Al-Mughira, Muawiyah, Khalid ibn Sa'eed ibn al-'Aas, and others from the Arabs who were named.  

أَنَّ النَّبِيَّ ﷺ اسْتَكْتَبَ عَبْدَ اللهِ بْنَ أَرْقَمَ فَكَانَ يَكْتُبُ عَبْدُ اللهِ بْنُ أَرْقَمَ وَكَانَ يُجِيبُ عَنْهُ الْمُلُوكَ فَبَلَغَ مِنْ أَمَانَتِهِ أَنَّهُ كَانَ يَأْمُرُهُ أَنْ يَكْتُبَ إِلَى بَعْضِ الْمُلُوكِ فَيَكْتُبَ ثُمَّ يَأْمُرُهُ أَنْ يَكْتُبَ وَيَخْتِمَ وَلَا يَقْرَأَه لِأَمَانَتِهِ عِنْدَهُ ثُمَّ اسْتَكْتَبَ أَيْضًا زَيْدَ بْنَ ثَابِتٍ فَكَانَ يَكْتُبُ الْوَحْيَ وََيَكْتُبُ إِلَى الْمُلُوكِ أَيْضًا وَكَانَ إِذَا غَابَ عَبْدُ اللهِ بْنُ أَرْقَمَ وَزَيْدُ بْنُ ثَابِتٍ وَاحْتَاجَ أَنْ يَكْتُبَ إِلَى بَعْضِ أُمَرَاءِ الْأَجْنَادِ وَالْمُلُوكِ أَوْ يَكْتُبَ لِإِنْسَانٍ كِتَابًا يُقْطِعَهُ أَمَرَ جَعْفَرًا أَنْ يَكْتُبَ وَقَدْ كَتَبَ لَهُ عُمَرُ وَعُثْمَانُ وَكَانَ زَيْدٌ وَالْمُغِيرَةُ وَمُعَاوِيَةُ وَخَالِدُ بْنُ سَعِيدِ بْنِ الْعَاصِ وَغَيْرُهُمْ مِمَّنْ قَدْ سُمِيَّ مِنَ الْعَرَبِ