KMnO4 solutions are dark purple. When used as a titrant, as soon as the endpoint is reached and the KMnO4- is in excess, the solution has a permanent pink hue (provided that the solution is initially colorless). Thus KMnO4 acts as its own indicator..............
KMnO4 solution is coloured. It is purple in colour and even a small pinch of KMnO4 give very dark colour to a solution.
Since we can see the colour change at the end point of a reaction, it can indicate the end point. So it can be used as an indicator.