Supervised Classification in ArcGIS Pro 

Some part of the built up is coming under crop land

This is actually a very common error for land cover classification. The reason is because the spectral similarities between urban and cropland. I, myself, have not come up with a good enough methodology to distinguish between the two. Of course, the time of the year influences the spectral characteristics. Bare ground will be similar to urban... But when crops have grown, you can expect a higher NDVI... So one option is to use images further into the growing season. If you don't have other imagery... This is not the answer you're hoping for... But I've learned that no supervised classification is perfect. Errors are natural and there will always be manual updates to your classification. I have not been able to fix the error difference between crops vs bare ground with 100% accuracy. My honest answer.

Thank you so much sir for the clarification 🙏.....

I've never heard of a waterlogged map. Would that just be everything classified as water?

@@SpatialZone No, It would be classify as waterlogged area and non waterlogged area