When you see (English Ver.), (Japanese Ver.) or (Korean Ver.) in brackets after a song title, the label is telling you which language the words are performed in. It marks a recording of the same song with the words performed in a different language from the original. The arrangement is usually the same or close, and the title is usually kept, so the bracket is what tells the two apart in a list.
It helps if we are clear about what the label is not. A language version is a separate recording. It is not a subtitle, and it is not a translation laid over the original audio. A subtitle track changes what you read, while a language version changes what was sung. Because it is its own recording, it can be listed as its own entry, which is why the label matters when a service lists the two together.
Where does it come from? Groups that promote in more than one country often re-record a song for that market, and the version carries the label so listeners and streaming services can tell the entries apart. There is a practical side to this. A language version often appears on a different release from the original, so the same song can sit on two records with different numbering, and the bracket is usually the only thing separating them in a tracklist.
Brackets in K-pop titles carry many jobs, so a language version and a 'Ver.' that means something else are easy to confuse. Read what is inside the bracket instead of assuming that each 'Ver.' names a language. One plain limit applies as well: which languages a song gets is a decision made by the record label, and there is no rule that a song must receive a language version at all.