How to use the excel filename as a value to populate new column, using Pandas?

[scidam]

Your files have regular names, so you can extract desired dates using index slicing, e.g. date = filename[:6].

I want to insert a new column called "Date" and use the "032018" to populate that column, etc for all 50 files.

So, you will get a data frame with at least 50 columns that have the same name Date? In any case, you will likely use either os.walk or glob.glob to get all file names. You can read about these modules in official docs here and here.

This isn't to be a hard problem, so it would be better if you post some code to show your efforts on solving the problem.