Saving Filename to a variable

I have a bot that reads excel file from a dump directory. I'd like to know if how I can retrieve the filename of a file and save it to a variable so that when I write the result file the original file name would be there.

Sample:
Original File name: CompanyABC.xslx
Output File: CompanyABC-Processed-2019-9-11.xslx

Have a look at the For Each File action (found under Actions -> Loop), this is typically the action used for iterating through files in a directory.
Each time a file is found the loop action allows you to assign the current file name to a text variable. This gives you the file name including the directory path.

You can then manipulate your file name variable using an Assign Variable action.
In this action, you can use expressions and converters in the value field to manipulate the filename to give you what you need.