I need users in my project to upload video content easily

I am running a guinness world record attempt for the most participants in a virtual band and need the participants to be able to easily upload their videos ready for editing.

I will not know who the participants are until they submit their videos.

Is there a GUI or and APP that can be used to give them access to via a web portal that we have created and for them to upload their content safely and securely. i.e. all they should see is their own personal uploading process and notice of successful upload and nothing else.