How do oceans, seas, lakes etc got salty?

Salt and nitrates occur naturally in the Earth's Crust. The oceans are salty because it all just kind of ended up there over millions of years.

Minerals dissolve, especially sodium and chlorine. Once in the water they never distill out. Given billions of years of erosion the ocean has enough salt that we can't drink it.

Rocks and minerals generally form at high temperatures. When it rains, the water reacts with those rocks and makes new minerals (generally eventually leading to clay and carbonate minerals) from the original metal-silicate salts. When the reactions happen, some of the components of the minerals dissolve into the water. Fresh water has very low concentrations of salts, but there are still dissolved salts in the water.

Rainfall that lands on ground eventually flows downhill through streams and rivers, and even through the ground (groundwater), which carries those dissolved salts down to the oceans (or isolated lake basins, lakes that do not have an outflow to the oceans). The water comes into those water bodies with the salts, and then the water evaporates to make new rain, but does not take the salts with it (the salts do not evaporate).

So, basically, small amounts of salts are always flowing in, but the salts do not leave when the water recycles through evaporation. The salt contents in the water bodies (oceans or salt lakes) rise as a result.

There are a lot of other things going on that help buffer the concentrations of specific salts, or serve as other sources of salts, but the main cause is simply that rock weathers to clay, carbonate, and oxide minerals, and in the process releases dissolved salts into the water, and that water ends up in the oceans.

Through the mixing of Metals and Halides such as table salt or sodium chloride. Rocks and minerals contain either or both.

- The ocean is salty because of disolved chemivals from earth's crust and washed in to the sea.

- Submarine volvanoes:
Solid and gaseous ejections from volcanoes.

- It also caused by weathering of continents.

Most of the salt in the oceans, seas, lakes etc actually come from land, rocks to be specific. The oceans, seas, lakes etc salty because it contains large amounts of dissolved minerals.