It is found in soap.
Caustic Soda (Sodium hydroxide) can be found in Pharmacies/Drug stores such as Boots.
Sodium Hydroxide (NaOH) A powerful base often used in industries.
we can get it in most chemical shops or hardware shops
No, it is mostly prepared from brine (The saturated solution of NaCl) by electrolytic method.
soda ash is mixed with slaked lime and heated, caustic soda and calcium carbonate is produced. This is regularly used in Paper & kraft mills.