As reported by WABetaInfo, WhatsApp added this new feature to the app’s latest beta version (18.104.22.168). The ability to share the screen is not available to everyone in the beta channel, but some fortunate users have had the opportunity to test it. When you are in a video call, the app displays a new button on the bottom bar that allows you to share your screen with the other party.
When you tap this button, a confirmation pop-up appears in which WhatsApp warns you about the risks of sharing your screen during calls. It informs you that the person on the other end will be able to see everything on your screen, including your payment information, passwords, photos, messages, and so on. To proceed, tap the “Start now” button, or tap “Cancel” to return.