Music copyright and consent for use

Hi everyone!
lately I have been wondering about the consents for using independently made music. If, say, someone makes a track that is not a cover or a remix and for example puts it up on youtube or soundcloud etc., no music label was involved, and if i would like to use that music in, say, a live stream on Twitch or wherever else what sort of consent do i need from the artist? And if i am f.e. in USA and the artist is in EU do i need an USA consent or an EU one? Or both? And would I need to file it in some government office or something like that?
Thanks for taking the time to read this guys