The capture? Currently the feature is only available in the beta version of WhatsApp and only for a few that use the preview of Android O Dev. That means there are only a limited amount of people who can use the feature right now.
The reason for the exclusivity of Android O Dev Preview is that the feature is possible thanks to a new API included in Android O, which unfortunately means that the vast majority of us will not be able to see or use this feature for quite some time. More than likely that once Android O becomes an official release in the near future, this feature will make its way out of beta and more to the consumer-friendly version of WhatsApp, although unless you find a work around – still Will require Android O or newer.