I heard that it is impermissible to utter the intention in Salah (Prayer) aloud. In this case, what should I say at the beginning of Wudu' (ablution) or Salah?
Uttering the intention out loudly or secretly in Salah, Wudu', and other acts of worship is impermissible, for the Prophet (peace be upon him) did not prescribe this either by saying or action, also because the place of intention is not the tongue, but the heart. You should start your prayer whether it is Fard (obligatory) or Nafilah (supererogatory) by saying - Allahu Akbar (Allah is the Most Great) - and start your Wudu' by Tasmiyah (saying, "Bismillah [In the Name of Allah]") to follow the Sunnah of the Prophet (Peace be upon him). You should intend practicing the acts of worship that you want by heart, except in case of Hajj (Pilgrimage) and `Umrah (Minor Pilgrimage), for it is prescribed to utter the rites of Hajj or `Umrah by saying: Allahomma (O Allah) (Labayk [Here I am! At your service] Hajj) or (Labayk `Umrah).The same goes for Hady (sacrificial animal offered by pilgrims) and Udhiyah (sacrificial animal offered by non-pilgrims), as it is prescribed for the person offering Hady or Udhiyah to utter after Tasmiyah: (Part No. 6; Page No. 319) "O Allah accept from me", or "from So and So", just like the Prophet (peace be upon him) used to do.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.