I am sure when one takes pictures you know sometimes it just drizzles or it's near say a waterfall and there's tiny tiny droplets of water on the lens am i right to say when they evaporate they leave a "stain" on the lens.
A water spot is an area of dried mineral deposits left on a surface after being allowed to air dry. Water quality, specifically the amount and type of minerals in the local water supply as measured by the total suspended solids or TSS test and other mineral levels such as sodium level, has a big effect on how severe water spots can be, for example on an automobile or dishes. Water spots can be avoided by drying after washing, using a "shammy" cloth or towel for a car and a good drying cycle in a dishwasher, or by manual drying or good drainage after manually washing dishes.
By the way, I notice you are starting a lot of threads wrt care of equipment. While that is good, try not to let this worry of stains/dust/etc impede the situations you would put your camera in to take photographs. Of course I'm not saying you should deliberately put your equipment in harm's way - that doesn't guarantee better pictures in any way; but try to think less about what will happen and concentrate on transforming your vision into photographs. Cheers!
dust/stain/smudges/water-marks (less than few square-millimeter) on the front element generally don't really show up in images, even at large f-stop numbers (smallest aperture opening), since the focal point is much much further away from the front element of the lens. just wipe or dab off at one's earliest convenience like what the bros say.
but take note any dust speck at the rear lens element (nearest to the sensor) will be noticeable in the image.