How do you convert sea or river water into drinking water?

By filtering and/or distillation.

You can not boil salt water to take out the salt. If you boil it you would have to catch the steam somehow. or by evaporation.

There are many ways, but the two most common are desalinization tablets and distilling the water. Reverse osmosis works well, as does water softeners. Both uses are elaborate in construction, but...

Several ways-- Distillation. The fresh water evaporates and is collected in a cooler place. This can be simple or complex. Rain is a distillation process. Heating up the salt water makes it...

It's called desalination. Yes, by the use of reverse osmosis we can convert sea water as pure water. It can also be purified through evaporation.