Hi Arhum
I'm not with Laminar Research, just a fellow simmer in the UK.
If you haven't downloaded global scenery for certain areas of the world, water only will appear!
To download areas of global scenery that you don't already have, open the X-Plane Installer app, and press the 'Continue' button a few times until you are presented with a global map.
From there, just click on the area of the world you are interested in and press 'Continue' again to proceed to download. Please see photo below of the page you need.
Warning, the download may take quite some time to complete!
Regards