From the command prompt, use this:
DIR <StartDir> *.jpg,*.pdf,*.ext /b /s >files.csv
Where <StartDir> is the 'root' of where you want to start the search from (eg C:\ for start from C: drive root.
You can have more file types to search than those three, obviously! Just change/add what you want to search for.
The list of files will be written into the file 'files.csv'. This will be able to be opened directly in Excel.
There's plenty of other switches that DIR can use simply enter DIR /? to see them.