If you need to make a phone call while you’re in public and you think that you need it to be more private, here are some stuff you can do:

Step from the crowd. If you are with people, make sure you excuse yourself. It’s the polite thing to do.

Find a place where it is more quiet and where you can speak without having to shout. Turn your face from other people and turn down the volume of the earpiece.

Cup your hand over the mouthpiece and talk softly. This will make sure nobody can hear what you’re saying.

Hang up when over. If you need to call back, find a more private place to do so.