Methyl orange and phenolpthalein are common chemical indicators often used in titrations. what is the role of a chemical indicator?

Explanation:

Chemical indicators:-

They are species or the substances which are added to the reaction mixture. They undergoes a specific and distinct observable change in the reaction mixture indicating  the formation of consumption of the species in the reaction mixture. The change can be a color change, olfactory change, etc.

Example:-

Methyl yellow which imparts yellow colour to the alkaline solutions and is red in acidic solutions.