When you download a new app, it's likely that you agree to the Terms and Conditions without fully understanding what they are. You could be giving an app access to your location, contacts, camera and microphone without even realising it.
When you download a new app, you should try to see what permissions the app wants so that you can decide whether you're happy to share that information. If you don't feel happy sharing that level of personal information, it's advisable to try and find another app to use.