Is this right that washing any body part or washing any thing three times will clean that thing. If it is so then there is no need of soap or washing powders. Is this true for taking bath also? If not then what is the exact way of taking bath (Ghusl).

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

One should differentiate between purity in the Sharee’ah (Taharah) and customary cleanliness. In fact, purity in the Sharee’ah differs according to the impurity to be removed. Some impurities have to be removed like human excrement; others need to be washed 7 times like the saliva of the dog; other impurities do not even need to be washed or removed, but just sprinkled with little water, like the urine of the baby who has not yet started eating and the Madhi if it comes out very often. Purity (Taharah) can be required without uncleanness as an Islamic ruling. For example, although the believing person may not be unclean, he/she is required to make Ghusl (ritual bath) for his/her whole body if he/she ejaculates following a lust. As for the customary or normal cleanliness, it does not take the ruling of the Taharah. Soap is for cleaning or removing some dirt that is stuck to the body, clothes, or the place. So, it is not similar to the Taharah and it does not require intention unlike the Ghusl (ritual bath) which requires intention.

Finally, we advise the questioner to study the chapter of Taharah in Fiqh as that will make things clearer to him.
For more benefit, please refer to Fatwa 370861.

Allah knows best.