The tashahhud taught by the Prophet (ﷺ) to Ibn Mas'ūd begins, "At-taḥiyyātu lillāhi wa'ṣ-ṣalawātu wa'ṭ-ṭayyibāt, as-salāmu 'alayka ayyuha'n-nabiyyu wa raḥmatullāhi wa barakātuh..." through the shahādatayn, and it is recited sitting in every tashahhud. After it in the final sitting one sends salah upon the Prophet with the wording he taught when asked how to do so: "Allāhumma ṣalli 'alā Muḥammad..." There is legitimate ikhtilāf on whether this salah is obligatory in the final tashahhud — al-Shāfi'ī and one report from Aḥmad hold it a pillar, while the majority (Ḥanafī, Mālikī) regard it as a strong sunnah — so a worshipper should never omit it.
Q&A · Prayer
What do you recite in the tashahhud, and is sending salah upon the Prophet in it obligatory?
Evidence — the daleel
Sahih al-Bukhari 831 ṢaḥīḥSahih Muslim 402 ṢaḥīḥSahih Muslim 406 Ṣaḥīḥ
On deen2u
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.