Books written about people (biographies) and books written by people about themselves (autobiographies) are found in areas relating to their primary subject. Many are in the history section (C-F), but many others are located in other places.
A couple of ways to find biographies:
Use Library Search -- type in the name you are looking for and "biography" and see what you get, if you want books, select Library Catalog under Sources. You will miss some titles this way, but you should get an idea of where they are located.
Choose Advanced Search, Select "Subject" and "exact" and type the name of your person -- last name first.
The results are different; both are useful. If you use the Browse search, you will find titles that librarians have assigned that name as a subject of the work. If you use Keyword/Anything search, you will get everything that mentions that person anywhere in the record.