The dua to make things easy is Allahumma la sahla illa ma ja'altahu sahla, wa anta taj'alul-hazna idha shi'ta sahla: "O Allah, nothing is easy except what You make easy, and You make the difficult easy if You will." It is reported from Anas ibn Malik in Sahih Ibn Hibban. Below it are the Quran duas for ease, with what each one means.
اللَّهُمَّ لَا سَهْلَ إِلَّا مَا جَعَلْتَهُ سَهْلًا، وَأَنْتَ تَجْعَلُ الْحَزْنَ إِذَا شِئْتَ سَهْلًا
Allāhumma lā sahla illā mā jaʿaltahū sahlā, wa anta tajʿalul-ḥazna idhā shiʾta sahlā
O Allah, nothing is easy except what You make easy, and You make the difficult easy if You will.
Sahih Ibn Hibban 974, from Anas ibn Malik; also Ibn al-Sunni, Amal al-Yawm wal-Laylah. Graded sahih by Ibn Hibban and al-Albani
رَبِّ ٱشْرَحْ لِى صَدْرِى وَيَسِّرْ لِىٓ أَمْرِى
Rabbish-raḥ lī ṣadrī, wa yassir lī amrī
My Lord, expand for me my breast [with assurance] and ease for me my task.
Quran 20:25-26, translation by Sahih International
رَبَّنَآ ءَاتِنَا مِن لَّدُنكَ رَحْمَةًۭ وَهَيِّئْ لَنَا مِنْ أَمْرِنَا رَشَدًۭا
Rabbanā ātinā mil-ladunka raḥmatan wa hayyiʾ lanā min amrinā rashadā
Our Lord, grant us from Yourself mercy and prepare for us from our affair right guidance.
Quran 18:10, translation by Sahih International
فَإِنَّ مَعَ ٱلْعُسْرِ يُسْرًا إِنَّ مَعَ ٱلْعُسْرِ يُسْرًۭا
Fa-inna maʿal-ʿusri yusrā. Inna maʿal-ʿusri yusrā.
For indeed, with hardship [will be] ease. Indeed, with hardship [will be] ease.
Quran 94:5-6, translation by Sahih International
سَيَجْعَلُ ٱللَّهُ بَعْدَ عُسْرٍۢ يُسْرًۭا
Sayajʿalullāhu baʿda ʿusrin yusrā
Allah will bring about, after hardship, ease.
Quran 65:7, translation by Sahih International
Our teachers will check the Arabic and transliteration on this page before launch.
Guide
The dua to make things easy is Allahumma la sahla illa ma ja'altahu sahla, wa anta taj'alul-hazna idha shi'ta sahla: "O Allah, nothing is easy except what You make easy, and You make the difficult easy if You will." It is reported from Anas ibn Malik in Sahih Ibn Hibban. Below it are the Quran duas for ease, with what each one means.
Say Dua 1 whenever something feels hard: a task at work, an exam, a move, a difficult conversation, a long journey. It is short, so you can say it under your breath at the moment you start. Many people add it to the duas they make after salah and in sujood. Dua 2 is the dua Musa made when Allah sent him to Pharaoh, a task far heavier than any of ours, and Allah answered him at once: "You have been granted your request, O Moses" (20:36).
Anas ibn Malik reported that the Prophet ﷺ said it. It is in the Sahih of Ibn Hibban, and Ibn al-Sunni included it in his book of daily duas.1 It is not in the six main hadith books. Ibn Hibban included it among the authentic reports, and al-Albani also graded it sahih. Rahat's teachers will confirm the grading before launch.
Many people say Rabbi yassir wa la tu'assir, Rabbi tammim bil-khayr ("My Lord, make it easy and do not make it hard, my Lord, complete it with good"). We could not find this wording in the six main hadith collections, and we know of no authentic chain for it to the Prophet ﷺ. Its meaning is good, so it is fine to say as your own dua, but do not call it a sunnah. The sunnah wording is Dua 1. The Prophet ﷺ did tell his Companions: "Make things easy and do not make them hard, give good news and do not drive people away" (Sahih al-Bukhari 69).2
Surah Ash-Sharh says it twice: with hardship comes ease (94:5-6). The Arabic says ma'a, with, not after: the ease is already there inside the difficulty, even when we cannot see it yet. Make dua, do your part, and trust Allah with the result. For more verses on this, see Quran verses about hardship and ease, and for studying, the dua for exams.
Questions
Allahumma la sahla illa ma ja'altahu sahla, wa anta taj'alul-hazna idha shi'ta sahla: O Allah, nothing is easy except what You make easy, and You make the difficult easy if You will (Ibn Hibban 974).
Rabbish-rah li sadri wa yassir li amri: my Lord, expand my chest and ease my task (Quran 20:25-26), the dua of Musa.
It is reported from Anas in Sahih Ibn Hibban and by Ibn al-Sunni, and Ibn Hibban and al-Albani graded it sahih. It is not in the six main books.
We found no authentic chain for it to the Prophet ﷺ. Its meaning is good, so you may say it as a personal dua, but the sunnah wording is Allahumma la sahla.