In order to use ‘Focus’ within the app, you will be required to open your Instagram Story. Thereafter, you will have to swipe under the ‘Record’ button which will be next to ‘Superzoom.’ Once you are done, you can focus the camera on a certain person/object and the image will automatically take the specific person/object into focus as the feature will blur the background.
As per Instagram, this option is currently available for all generations of iPhone 6S to iPhone X. Moreover, it is also available to ‘selected Android devices.’
Image Source: TheNextWeb