Tawhid: means attributing Oneness to Allah and describing Him as being One and Unique, with no partner or peer in His Essence and Attributes.
Three Categories of Tawhid: Tawhid-ul-Rububiyyah (Oneness of Allah’s Lordship); Tawhid-ul-Uluhiyyah (Oneness of Worship); and Tawhid-ul-Asma’ wal-Sifat (Oneness of Allah’s Names and Attributes).
Short Explanation of Tawhid with evidence(Daleel) by the esteemed renowed scholar Sheikh Salih Al Fawzan.