Add column showing source name.

[countryfan_nt]

Hello friends, Hope all is well!

I have combined Txt files from folder with PowerQuery, but wish to add column displaying the file source. e.g. Jan-Rev-2021 etc.
Please help me with code/formula.

Thank you and all the Best,

 

[RoryA]

How exactly did you combine them? I get the source file name as the first column by default.