Hi Amy. I'm Greg, 10 years awarded Windows MVP, specializing in Installation, Performance, Troubleshooting and Activation, here to help you.
The only Documents folder that should matter is the shell Documents folder which is signified by the icon of the document on it, and is located at C:\Users\Your Use Name along with all other shell User folders with the official icons on them.
Any others can be deleted after copying the files into the shell Documents folder, comparing them if they're duplicates to make sure you keep the latest version. Explorer will let you do this during the copy process when it finds duplicates.
You mentioned Onedrive Documents folder. You can move the official shell Documents, Pictures and Desktop folders into OneDrive to backup and sync in real time to the cloud where they're safe from ransomware, theft and fire. See here how to do this if you want: https://www.tenforums.com/tutorials/116029-turn...
Once you have this all sorted out if there stlll remains Documents folders in the Explorer bar on left, you can right click to Remove them after copying their files into shell Documents folder, then delete them entirely if they bother you further. Sometimes if you move your User folders to another drive or into Onedrive, an app which is badly coded may recreate your default Documents folder to place itself in there. But otherwise there should not be extra Documents folders except at C:\Users\Public which has a set of folders for easy sharing on your network if you want that. These can be ignored but not deleted.
I hope this helps. Feel free to ask back any questions. Please report back results for all steps given so I know what else to suggest if necessary.
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