It is narrated from Ka'b bin 'Ujrah (may Allah be pleased with him) that the Prophet (ﷺ) used to recite in prayer: "O Allah! Send mercy upon Muhammad (ﷺ) and upon the family of Muhammad, as You sent mercy upon Ibrahim (peace be upon him) and upon the family of Ibrahim, and send blessings upon Muhammad (ﷺ) and upon the family of Muhammad, as You sent blessings upon Ibrahim (peace be upon him) and upon the family of Ibrahim. Surely, You are Praiseworthy and Glorious."
Hadith Referenceمسند الإمام الشافعي / كتاب الصلاة / 258
Hadith Takhrijأخرجہ البخاری، أحادیث الانبیاء، رقم: 3370 - ومسلم، الصلاۃ، باب الصلاۃ علی النبی ﷺ بعد التشہد: 406۔