Ensure your Android device has internet connectivity and then run the Google Play Store app from the home screen or the app drawer.
Using the Play Store’s search feature, look for an app called ‘Truecaller’. This is a free app and you need to install it to proceed further.
Once installed, run the Truecaller app. The first screen will require you to select your country and tap next.
On the next screen, the app will ask you to connect to social networks like Facebook, Twitter and Linkedin in order to get additional contact details.
After connecting to your social networks, you will be presented with the ‘auto match’ option, enabling which will match your phone contacts automatically with your social network contacts.
The free caller ID reveal feature is what you are looking for. However, in order to avail that, you need to agree to sharing your own contact data with others first. No one will be able to browse through your contacts, but people will be notified if they get a call from someone on your list.
Now if you get a call from an unknown number, the TrueCaller app will check for that number in its database and provide you a name and other information to go with it. This way you will know who you are talking to.