In the Contacts app, tap on your card at the top to get started. You'll see My Card under your name.
Tap Edit in the screen's upper-right, then Edit under your contact photo.
Various choices are available for creating a poster, including using an image like a selfie or a Memoji representation. Additionally, users can generate a simple Monogram poster that showcases initials or use the Camera feature to capture a picture instantly.
Creating a poster in this interface resembles designing a Lock Screen in iOS 16. Users can select a photo from their library, with vertical images preferable.
Photos captured using Portrait Mode are particularly suitable as the phone can effectively distinguish the subject from the background, allowing for the application of color effects.
To navigate through different filters that distinguish you from the background in the image, swipe left or right. By tapping on the color circle at the bottom right, you can select an accent color of your choice.
To personalize the font, color, and weight, tap your name at the top of the screen. You can use two fingers to zoom in and out or drag the picture around on the screen.
Once you're satisfied, tap Done to see a preview of the Contact Poster, and there is an option to add it as a contact photo.
Source: Appleinsider