Her title of "Doctor" (of Humane Letters) is an "honorary degree" given largely to those who have shown 'humanitarian' and 'development professionalism'. All her 'doctorates' were received while she was the wife of VP Biden.
There is no academic studies or knowledge needed, and the most common way to receive this "degree" is through large sum donations, or social/political favor. She did not attend any the five colleges that granted her "Doctorates".
Her working resume at this time included waitress, model, substitute teacher, mother, wife x2 and Lady VP.
Her academic resume includes Brandywine Junior College in PA for one-semester and BA in the English Language, which she has spoken since birth, from the University of Delaware that she used to be employed as a substitute teacher for less than 1 year.
“Biden later returned to school for her doctoral degree, studying under her birth name, Jill Jacobs.[34] In January 2007, at age 55, she received a Doctor of Education (Ed.D.) in educational leadership from the University of Delaware under the direction of professor Barbara Curry.[1][43][44][45] Her dissertation, Student Retention at the Community College: Meeting Students' Needs, was published under the name Jill Jacobs-Biden.[44]“
https://en.m.wikipedia.org/wiki/Jill_Biden#Education_and_career,_marriages_and_family
FWIW.