I'm a student in the last year and i have some good videos online with sound design made by me, how can i get my sound design videos/portfolio to american companies?
These are my sites.
By knowing people who work in said American companies (esp. in marketing).
By interning/working in an audio (post) production house that does a lot of the productions that you're interested in.
By knowing freelancers that do said productions and getting them to hand you some of their work (e.g. editing) and forming a partnership that way.
By establishing yourself as a freelancer (very difficult).
Prepare to compete a lot.