iPhone has a finder option that enables the user to search the whole phone for the matching keyword that we enter. Is there something similar for Android?
Android has Google Search. In the homescreen, long-press the left soft key of your phone to trigger the search.
Also, if your phone has a Google app, launch it. Then click the left soft key to open a menu. Click
Settings, and you will find
Phone Search. You can select which items to search.
As @geffchang points out, you can use the Google search facility. It doesn't just search the web, but items on your phone too. Usually it searches your phone as you type, and provides a button to go to a web search, but that's different in different versions. The way you get to it depends on what device you have.
If you have a big box labelled "Google" on your home screen, tap that and enter text. (Nexus devices tend to have this.) You might instead have a button with that label on your home screen: tap it.
If your device runs Jelly Bean (i.e. it comes with Google Now) and has on-screen soft keys for back, home, and recent apps, hold your finger on home. A ring will appear (like the one you get on the lock screen). Drag over to the "Google" button and release.
If your device has a hardware search key, whether it's a physical key or a capacitive one, go to the home screen and press the search key (which looks like a magnifying glass). These days I think only HTC phones and some unbranded ones have them. If there isn't a search key but there is a menu key (most Samsung phones), long-press that instead.
If none of the above methods work for you, go to the app drawer (the list of all apps) and look for one called just Google. Start that app. If you often want to search, and that's too long a process, there's a home screen widget (called Google Search) that adds the same search bar you find on Nexus devices.