So soldering is useful for electronics and joining copper metal. And it's a process wherein the base metal stays solid and doesn't melt. The solder itself melts, but the copper stays solid. In that way it's very, very similar to brazing, which is another technique in that the base metal also stays solid.
Now, brazing takes place in higher temperatures. And it's sort of arbitrary distinction, but brazing may take place at several hundred degrees Fahrenheit higher than soldering. Now, welding is a similar process of joining metals except that in welding the base metal itself also melts. So not only does the filler metal melt, but also that the base material.
So you have this sort of spectrum. Soldering at low temperatures, brazing in the middle, and welding at the highest temperature. Now at the low end of the temperature spectrum, soldering is useful, not only for electronics, but also for plumbing and in the use of jewelry manufacture. Where you're dealing with gold and silver metals.