Hello, by clicking on settings (Viber), option delete call history. Otherwise, on some touchscreen smartphones, press and hold on the received call and a page will appear: delete.
gissay
This solution doesn't work on iPhone.
mag
Thank you, the long press on the call works; so you need to long press on the call then delete on the trash bin icon at the bottom right.
Coco
I proceeded by pressing and holding the call, then clicking on the trash can at the top right. And it works, thank you for your advice!