The Camera app captures a photo in both the DNG RAW format and JPG format.
Digital Negative (DNG) is an open-standard lossless RAW image format. Since a RAW file is typically 2 to 6 times larger than a JPEG file and is not viewable in most photo viewer apps, a photo is captured in both DNG and JPG formats. When you use the Google Photos app, you'll see a icon on a photo to indicate that there is a DNG RAW format version of the file.
RAW photos are not processed when captured to preserve most of the original image data—such as dynamic range—so you can adjust lighting or make professional adjustments using advanced editing tools. After making adjustments, save the RAW photo as a JPG file if you want to print or share it.