A mockup is the image of a device frame, empty screen, in which you insert a capture to show a site or application in its usage context. On a sales page, portfolio, or client presentation, the same capture placed in Apple iPhone 11 Pro Max is immediately readable as a smartphone interface.
This file is a PNG with a transparent background: the device outline and screen area are empty, saving you from any cutting out. You place your capture on the lower layer in Figma, Sketch, Photoshop, Canva, Keynote, or PowerPoint, and the frame overlays neatly, even on a colored background, gradient, or photo.
For a sharp rendering, prepare your capture at the screen ratio, ideally at its native resolution of 1242 x 2688 pixels. The free version is exported in 397 × 800 pixels, more than enough for a screen; the high-definition version goes up to 1308 × 2633 pixels and covers printing as well as tight cropping. Other models are available in the same format, all downloadable for free: iPhone, Samsung Galaxy, Google Pixel, iPad, and laptop mockups.