What does inplace=True do in reset_index()?

https://www.codecademy.com/paths/data-science/tracks/data-processing-pandas/modules/dspath-intro-pandas/lessons/pandas-i/exercises/reset-index

I understand that drop=True here is to delete the original index while we are making new index. However, I don’t get the idea of inplace=True part here although the lesson mentions that “using inplace=True, we can just modify our existing DataFrame.” I tried to test df2 with and without inplace=True and cannot find the difference. What does inplace=True do and when do we use it? or when do we need to set it as False?

df3 = df2.reset_index(inplace=True, drop=True)

This would be something to find out by reading the documentation for that method