The Facebook App on iOS and Android has access to your location details due to settings on their app, this information is used to gain a general idea of users movement and purchasing habits. If you spend a long time in a store, you may then see more ads on Facebook reminding them to shop there again.

To change this open Facebook App – go into Settings, Account Settings, Location and turn off location tracking and
location history. Changing this setting should stop this tracking by Facebook.

Facebook also monitors which apps you use most often to determine what ads to show.

On Apple iOS go into Settings, Privacy, Advertising, turn on Limit Ad Tracking.
Android users can go to  Settings > Google > Ads > Opt out of Ads Personalization.

To disable Facebook’s access to your microphone, many people question why would Facebook need access to your microphone.

On iOS, go to Settings, Privacy, Microphone, Facebook and disable Facebook’s access to the microphone.
On Android, go to Settings, Apps, Facebook, Permissions, Disable microphone.

Let me know if you have more questions.