WhatsApp is a free messaging app that you can use on your Android phone.
It is easy to download to your device and does not take up much space. WhatsApp also has robust security, providing beginning-to-end encryption for anything you send.
The app allows you to send both text messages and voice messages, as well as other files. You can share documents, images and videos, as long as they don't exceed a certain size limit.
WhatsApp also allows you to make both voice and video calls.
The app gets updated often with new features, and it also backs up all files to your Google Drive account.