(This is your 2nd thread on the same issue, as the previous is...)
This is the preset location to save a wordpad documents; default saving. C:\Users\user\Documents
You can check on the C: root drive and/or on this folder C:\Users\user
Next time try to save to only on your user documents folder first before copy to another folder.
Now, you are worried, as you cannot find the file, as you may had did several amendment.
But not to worry as the file should be still intact.
Click on the Window Icon, using the search, type the filename slowly, as it will show all.
Meaning, if you type, ex. abc it will show matching filename starting, abc
This is only the best way to search for filenames.
Edit:
Have you check on the external HDD root directory, ex. D:\ or E:\