I hope this helps!
Best of luck!
Associate’s degree - a two-year degree, typically in an applied field connected with a specific job (AAS) or in preparation for transferring to a four-year school (AS or AA)
Bachelor’s degree - a four-year degree, typically what someone means in the US when they say “college degree”; there are many different kinds, but they amount to equivalent levels of education
Professional degrees - these are graduate degrees and require a bachelor’s degree, but a special subclass, like the JD (juris doctor, the first legal degree)
Master’s degrees - these are graduate degrees and require a bachelor’s degree, but exist across many fields
Doctoral degrees - these are graduate degrees, require a bachelor’s degree (and possibly a master’s degree), and are usually the terminal degree for a field (as in, there are no further academic credentials available)
This could be full-time, part-time, online, or any other format and take any length of time. You are an undergraduate student as long as you are pursuing your Bachelors degree.
A graduate student has completed their Bachelor's degree, and is now pursuing an additional degree, This could be any type of Graduate Diploma, Graduate Research, Masters, PhD, or other study/work - where a Bachelor's degree is usually a minimum requirement.
It is possible to do both a Bachelor & Masters course at the same time - though these are very uncommon.
In most cases you will need an undergraduate (Bachelor's) degree in order to pursue a Master's degree. However, to describe it simply, think of your undergraduate degree as a little more "generic" degree. Then think of a Master's degree as a more granular degree in a particular focus area and is usually more career focused. Let's say that you got an undergraduate degree in Finance, but decide you want to take it further. Then you could attempt to get your Master of Business Administration. You have a degree in Finance regardless, but an MBA will help further fine tune your skills. Hope this helps!
To be very concise, an undergradaute student is a student undergoing a bachelors degree course while a graduate student is a student that has completed this bachelors degree and is envisaging going for higher degrees like Masters, doctorates and more.
Bachelors degree is the stage after passing highschool final exams