It's not possible to have the online manuals password.
Have you tried downloading a copy and saving that? You may need to have the Pro version of Acrobat DC or an equivalent to redact or save bookmarks.
Bay Area - CA
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I do have Acrobat Pro. The bookmark icon is pale and not active. I can download and "print" the manual, then I can have bookmarks, but loose all of the links. I guess I cannot have it all. Thanks.