What is the text of the supplication that is recited after Surat Al-Fatihah and begins with "O Allah, bestow Your prayers and peace upon our Master Muhammad..."?

There is no evidence for the legitimacy of invoking blessings upon the Prophet (peace and blessings be upon him) in the five daily prayers and supererogatory prayers immediately after Al-Fatihah. As for the funeral prayer, invoking blessings upon the Prophet (peace and blessings be upon him) is prescribed after the second Takbir, followed by supplication for the deceased after the third Takbir, as indicated by the saying of Abu Umamah: "The Sunnah in the funeral prayer is to recite Al-Fatihah, invoke blessings upon the Prophet (peace and blessings be upon him), and then offer sincere supplication for the deceased until it is finished." There is no reported supplication from the Prophet (peace and blessings be upon him) or invoking blessings upon him after Al-Fatihah outside of prayer. Furthermore, the honorific "Sayyiduna" (our master) has not been authentically reported as being mentioned in prayer by the Salaf.