Most applications to US universities are made through the Common Application website: https://www.commonapp.org/ with the exception of universities in California, Florida, Texas and MIT. Please look at the individual websites of the universities for full details of how to apply.
It is possible to apply to US colleges via The Universal College Application or Coalition for College Access instead, but not all colleges are included in these applications.
The Common Application has a requirements table that contains all deadlines, fees, and entrance requirements.
There are three deadlines:
Early Decision (binding) deadline early November
You may apply for one early decision course, and, if offered a place, it is understood that you will reject all other offers to take the place.
Early Application(not binding decision) deadline early November
This early deadline is not a binding decision – if you are offered a place, you do not necessarily have to take it.
Regular Decision(not binding) deadline end of December
This is the standard application deadline. Any offers made by colleges are not binding – you do not have to accept them.
You can apply during all 3 phases
Additionally, there is lots of information on the Education USA website:
Information about studying in the USA www.educationusa.info (office in Paris)
As international travel is now becoming quite limited, there are lots of virtual opportunities for you to meet representatives from the universities and visit the campuses.
We cannot stress enough the need for the university and course to be a match for the student as they are all very different. If you can visit or attend an open day then please do so. Otherwise, and given the current health situation, there are University Virtual Open Days: See university websites for dates or ask them if you can visit