Hey @ankit!
There are external tools to Prismic that we usually recommend adding into your projects, one of them is Algolia. It allows you to you quickly build a search interface in your front-end.
Algolia has a widget called The VoiceSearch widget. It lets the user perform a voice-based query. We don’t have any examples yet to show how it works with Prismic. But you can check out Algolia’s examples, they guide you step by step to add their widget to your project!