What is Copyright? It is a type of intellectual property that gives its owner the exclusive right to make copies of a creative work, usually for a limited time. The creative work may be in a literary, artistic, educational, or musical form.
What is Fair Use? The doctrine in United States law that permits limited use of copyrighted material without having to first acquire permission from the copyright holder.
These two things go hand in hand because people who make objects, write books or music, or do anything for education and make their money from these things they can't have other people stealing their ideas so they have to put a copyright on it. We have to use fair use so they don't lose any money on what they are trying to sell. This just means that we will be able to use certain things to a certain point and after that we will not be able to use that material any longer without having to pay for it.
I am providing links below that will help you better understand Copyright and Fair Use:
https://www.templetons.com/brad/copymyths.html
https://www.theedublogger.com/copyright-fair-use-and-creative-commons/
https://cmsimpact.org/resource/fair-use-frequently-asked-questions/