As of my last update in January 2022, the iPhone camera app does not have a built-in feature to blur the background while taking a photo. However, you can achieve a similar effect using the Portrait mode available on certain iPhone models.

Portrait mode uses computational photography to create a depth-of-field effect, where the subject is in focus and the background is blurred. Here’s how to use it:

1. Open the Camera app on your iPhone.
2. Swipe to the “Portrait” mode. This mode is typically represented by an icon that looks like a person’s head.
3. Position your subject within the frame. The camera will indicate when it detects a subject to focus on.
4. Tap the subject on the screen to focus on it and set exposure.
5. Press the shutter button to take the photo.

Keep in mind that not all iPhone models support Portrait mode, and the effectiveness of the blur effect may vary based on factors like lighting conditions and the complexity of the background. Additionally, newer iPhone models may offer more advanced features and improvements to Portrait mode.