Generally, Japanese don't say 「私は～学士です」or「～学士号を持っている」, we usually say 「～大学～部～科卒です」,「～大学～部～科を卒業しました」, or「～大学～部～科を出ました」. And, when a person applies for a job, we write it down on a resume as 「～大学～部～科　卒業」 Here is a sample of a resume. https://tenshoku.mynavi.jp/knowhow/rirekisho The differences between 博士, 修士 and 学士 are already mentioned by Uedaさん. Here is the specific information about 博士, 修士, and 学士, would you please check some lists on around the middle of this? https://www.toishi.info/email/degree.html

どういたしまして。

Uedaさん、お返事ありがとうございました！

You usually use "学士” for bachelors, "修士" for masters, and "博士" for doctors in Japan. The first one is not so frequently used as the others are, though. You more often just say "大卒", while you usually say "院卒" for masters and doctors. Here in this sentence, "院" means graduate school and "卒" means graduation. "院卒" means people who finished graduate school.