1. Open WhatsApp and go to Settings > Notifications > New chat tone.
2. Select a preferred tone from the list of available ringtones or choose "Add tone" to import a custom one.
3. To add a custom ringtone, go to your phone's settings, select Sounds & vibration, then Ringtone, and select the desired audio file. Then, go back to WhatsApp's New chat tone and choose "Add tone."
4. Browse your phone's media files and select the newly added custom ringtone.
5. Save your changes by selecting Done or Back.
Alternatively, you can download WhatsApp's official ringtone packs from the Google Play Store or Apple App Store. These packs include a variety of tones to choose from. Just download, install, and select your preferred pack in WhatsApp's New chat tone settings.