Whether Opus can compare files query

I have a number of files which are stored in two different formats (eg *.wpd and *.txt).

They are stored in a number of -sub-folders off one main folder

I wish to see whether for each *.wpd there is an equivalent *.txt file.

Is possible to use the compare function or some other feature in Opus to do this?

No, I think you'll need a tool like Beyond Compare or WinMerge.

Not sure which of those types of tools understand WordPerfect and can convert it to text on-the-fly for comparison with a text file.

You can run the tools from Opus, if you find one that works. See the Diff/Merge toolbar in the Toolbars part of this forum for a bunch of examples.