بِسْمِ ٱللَّٰهِ ٱلرَّحْمَٰنِ ٱلرَّحِيمِ

Below will be a short list of some of the judges, administrators, governors, secretaries and tax officials under the Caliphate of Abu Bakr al-Siddiq:

Abu ‘Ubaydah – took care of finance
‘Umar b. al-Khattab – took care of judicial matters, though he stayed in office for a year
Zayd b. Thabit – served as his secretary

‘Uthman b. ‘Affan – provided him with information
‘Attab b. Asid- was his governor of Mecca
‘Uthman b. Abi al-‘Asi – was in charge of al-Ta’if
Al-Muhajir b. Abi Umayyah – was in charge of Sana’a
Ziyad b. Labid – was in charge of Hadramawt
Ya’la b. Umayyah – was in charge of Khawlan

Abu Musa al-Ash’ari – was in charge of Zabid and Rima
Mu’adh b. Jabal – was in charge of al-Janad
Al-‘Ala’ b. al-Hadrami – was in charge of al-Bahrayn
Jarir b. ‘Abdallah – was in charge of Najran
Abdallah b. Thawr – was in charge of district of Jurash

‘Iyad b. Ghanm al-Fihri – was in charge of Damat al-Jandal
Khalid b. al-Walid – was Commander-in-Chief
Abu ‘Ubaydah al-Jarrah – in Syria He was in command of a division
Shurahbil b. Hasanah – in Syria he was in command of a division
Yazid b. Abi Sufyan – in Syria he was in command of a division

[Tarikh al-Tabari]