On the iPhone, assigning Custom Alert Tones to select WhatsApp Contacts might help distinguish key WhatsApp Contacts from the others.
You may, for example, apply a Custom Alert Tone to an essential WhatsApp Contact so that you know when you get a WhatsApp Message from that person right away.
Similarly, setting up separate Alert Tones for each member of your family on WhatsApp will help you remember to check and reply to critical messages from your loved ones.
Steps to Assign Custom Alert Tone for WhatsApp Contacts
Currently, the only way to assign Custom Alert Tones for specific Contacts on iPhone is by using the Contacts App.
Open Contacts App > select your Contact > On Contacts Info screen, tap on the Edit option located at top-right corner.
On the next screen, select the Text Tone option.
On the Text Tone screen, scroll down to “Alert Tones” section and select the Alert Tone that you would like to assign for this particular WhatsApp Contact.
To preserve this option for future calls from this Contact on your smartphone, tap Done.
When this Contact sends a WhatsApp Message to your iPhone, your device will notify you by playing the Custom Alert Tone you specified for this Contact.