in jee mains application I made a mistake in place of residence, instead of rural I mentioned urban , is it necessary to get it corrected ?

Hello,
Yes it needs to be corrected. It won't be any problem but giving a wrong information is a mistake. The board will release dates when to change the mistakes. So check for this notice in the official webpage of NTA and correct it accordingly.
Don't make this mistakes as a single mistake will lead to elimination of your application. So be attentive while filling the form.
Hope it helps!