What does advaita vedanta philosophy says?

Sankaracharya is considered the main teacher scholar who introduced the concept of advaita vedanta. There were other scholars also who added to this concept and strengthened it. Literally it means learnings from the Vedas in a non-dualism way. Many followers of the Sankaracharya propagated these concepts and a new philosophy of advaita vedanta emerged out of it. Indian Vedas are well known for the immense knowledge and teachings which they contain and worldwide the scholars have studied and worked on that ocean of wisdom and prudence and given out their research work on those premises. The word Vedanta means the end of the Vedas which technically means takeaways from Vedas and modifications in them in light of the non-dualism theories about the relationship between the Brahman (spiritual energy) and Atman (soul). Vedas were supplemented by Upnishads which were a link between the Vedas and the scholars of that time and Sankaracharya kept this tradition alive by making more commentaries on the Vedic principles. Those learnings are known as Vedantic learnings and the theory of non-dualism added to it led to Advaita Vedanta philosophy.

The philosophy of Mayawad was established by Sripad Sankaracarya. This doctrine believes in the theory that Brahman or Spiritual Energy is the truth and ultimate of everything. It is a part of the divine power that is God which is the supreme. Everything else is like an illusion and we do not able to differentiate between this illusion and that divinity. The interesting thing about Mayawad is that they consider the creation of Lord Krishna also as an act of Maya. Actually the word Maya means to create some illusion. Some scholars oppose this view of the people believing in Mayawad. This philosophy is also created only through commentaries on Vedantic learnings only.

The Vedas were full of knowledge and learnings and scholars had interpreted them in different ways putting their own commentaries and it so happened that some of the philosophies like Advaita and Mayawad emerged as new philosophies under the umbrella of Vedantic Philosophy.

Advaita can be defined as not being two and is a name given to a school of Hinduism stressing on the non dual nature of the ultimate truth. In the simple term, we and the supreme being ( Brahman) are not different signifying that we are a part of Brahman and will ultimately become Brahman again when we reach the Mukti/ liberation. In one of the Mahakavyas of Advaita denotes Tat Tvam Asi which means that you are being referred to Brahman.
Against this, Davaita ( Dual) Philosophy of Hindu states that we are different from the supreme being. Once we attain liberation, we get the opportunity to interact with the supreme being in the personal form but can never achieve the true form of supreme being.