I received an email saying there was a reply but it has disappeared.

It suggested that for the Desktop version, available from the App Store, no smartphone was needed. Unfortunately, when you first open the App on the imac it displays a screen saying:

Quote:
Open WhatsApp on your phone.


Back to square one!


iMac (Retina 5K, 27-inch, 2017); 3.8 GHz Intel Core i5; 2TB HD; 64 GB 2400 MHz DDR4 RAM; Radeon Pro 580 8 GB. iPad Pro 10.5" Model MPME2B/A with 512GB capacity; iPhone SE 2020 256GB