Would all the different species evolve to their respective next form of life eventually? Like this generation apes to humans in next million years? Or does all the different species exist to only show how evolution happened to humans?
For example, it seems foxes can evolve into dogs by domestication, is that so?
There are a lot of misconceptions in your question. The better for you would be to simply start with an intro course to evolutionary biology such as Evo101 by UC Berkeley for example. I will answer your question directly in the text.
would all the different species evolve to their respective next form of life eventually?
You seem to have a very discrete conceputalization of what form living things can take. Current species won't all of a sudden change into a new one, like a "pokemon evolves". But all current lineages are still evolving. They keep changing gradually.
Like this generation apes to humans in next million years?
Humans have not "evolved from apes". Humans ARE apes. Humans and other apes have a common ancestor who already was an ape. The most closely related species to humans are chimpanzees and bonobos. The Most Recent Common Ancestor (MRCA) between humans and either chimpanzee or bonobos lived about 6 millions years ago.
See this answer for a short intro to phylogeny. You might also want to explore the tree of life by yourself on OneZoom.org. You'll find the human lineage here.
Or does all the different species exist alive now to only show how evolution happened, to humanz?
No, there is no intention. Nobody made evolution happen for humans to witness it. Evolution just happened and keeps happening. Nothing has stopped it and nothing (except extinction of all life on earth) can stop it.
If you follow a very short intro to evolutionary biology (such as the Evo101 suggested above), you'll understand what evolution is and why it always happens.
Though it seems foxes can evolve into dogs by domestication?
No. Some foxes are currently being domesticated and they manage to select for typical domestication traits (e.g. lower aggressivity). These domesticated foxes are not dogs and never will be. They are domesticated foxes. If those domesticated fox become different enough from wild foxes (typically if there is reproductive isolation), then we will eventually consider them as a new species and give a name to this species. But we should not call them dogs, they are not dogs (just like cats, cows, chicken or corn are different from dogs, yet all are domesticated).
You have so many misconceptions about evolution, it is impossible to give you a complete answer in a small text box
There is no "next form". Populations change in response to their environment, and how that happens is in large part dependent on chance.
Foxes do not evolve into dogs. Nothing the scientists did in that experiments was anything remotely like making foxes evolve into dogs. All they did as put the population under enormous pressure by culling all but the friendliest animals.
