I have tested kill process by giving the path of “*.eml” file but it is not working, file is not closing.
What would work most likely is e.g. “OUTLOOK” in the process name depending on the app you are using for such files. If you want to get the list of the processes you are currently using, you can do this via “Get Processes” activity. See e.g. Print all processes
File is not a process. You can’t “kill” the file. You need to find out the process which is taking your file and kill this process instead.
but just like start process i assigning only file path same as i want to close that file
Start Process you need to define a path to executable file. Can you show how are you starting .eml file?
You can do it with “Close application” instead - just “Indicate on screen” your opened .eml file.