That entirely depends on what sort of vocal reverb effect you want. I'd suggest that you start with either "Vocal I" or "Vocal II" factory preset ("Manage" button > Factory Presets") and adjust as required.
What is the best settings for reverb in Audacity? (For vocals/singing)
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Please state which version of Windows you are using,
and the exact three-section version number of Audacity from "Help menu > About Audacity".
Audacity 1.2.x and 1.3.x are obsolete and no longer supported. If you still have those versions, please upgrade at https://www.audacityteam.org/download/.
The old forums for those versions are now closed, but you can still read the archives of the 1.2.x and 1.3.x forums.
Re: What is the best settings for reverb in Audacity? (For vocals/singing)
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)