Right click on that file > Properties > Copy the location
Let's say that this is c:\sample\mydoc
Type cmd in Windows Start Search box
Right click on cmd > Run As Administrator
In cmd box type cd and press space bar to give one space and right click to paste the folder path > Enter
Hence you needed to give cd c:\sample
Now, your directory will be changed to your folder
You can put following command
del filename.extension
Hence, if your file name was test123.docx, you need to write
del test123.docx
Note if there is a space in file name, you will have to enclose in double quotes
Hence
del "my file123.docx"