Answer:
(Fatwa: 1136/1136=M/1430)
It is not necessary; rather it is mustahab just after completing the Quran to recite Surah Baqarah till the verse 5 and then recite the dua of Khatm-e-Quran. It is narrated in haidth that the Prophet (صلی اللہ علیہ وسلم) was asked:
ای الاعمال افضل؟ قال: الحال المرتحل الخ وفی کنز العمال شرحہ: الخاتم المفتح
i.e. O Messenger of Allah! Which is the best of actions? He replied: One who completes and at the same time begins.
Allamah Al-Suyuti writes in Al-Itqan with the reference of Al-Darami that whenever the Prophet (صلی اللہ علیہ وسلم) recited Surah Al-Nas he used to recite it with the first 5 verses of Surah Baqarah and then recite the dua of Khatm-e-Quran.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband