Should we say "O Allah, send blessings upon Muhammad" or is it sufficient to directly send blessings upon him without asking Allah to do so, based on the verse: (Indeed, Allah and His angels send blessings upon the Prophet. O you who have believed, send blessings upon him and grant him a thorough greeting)?

Allah revealed the Quran to Muhammad, peace and blessings be upon him, and charged him with clarifying whatever needed clarification, as Allah Almighty says: "And We have sent down to you the Reminder that you may make clear to the people what has been sent down to them," and His saying: "And We have not sent down to you the Book except that you may make clear to them that wherein they differ." The Prophet indeed clarified how to pray upon him. It was narrated from Ka'b ibn Ujrah, who said: "Say: 'O Allah, bless Muhammad and the family of Muhammad, as You blessed the family of Abraham, You are indeed Praiseworthy, Most Glorious. O Allah, bestow Your grace upon Muhammad and the family of Muhammad, as You bestowed Your grace upon the family of Abraham, You are indeed Praiseworthy, Most Glorious.'"