You have two choices to create black and white photos on iPhone. You can either take photos in black and white in the first place, or take photos in color and then convert them into black and white afterwards. Check out details below.
Take black and white photos on iPhone
By selecting visual effects, you can quickly create B&W pictures on iPhone. Run the stock Camera app on your device, tap the Effects icon, then choose an effect, such as Mono, Noir, Silvertone, after that point your camera and shoot to take black and white photos directly. This is the easiest way to create black and white pictures on iPhone.
Convert black and white photos on iPhone
We recommend you take photos in color, then convert them into B&W on iPhone. By doing so, you will have both a color version and a B&W of the photos in your Camera Roll. Although it requires the extra step of removing the color in post-processing.
Launch the stock Photos app on iPhone, select the image you like to edit. Press the Edit button, choose Effects, then browse through the effects to preview and apply. See below screenshot.
Converting black and white photos on iPhone as an advanced user
Recent iOS and iPhone models also have more advanced settings and parameters for skilled users who like to customize their black and white photos. Again open the Photos app on iPhone, select Edit, then touch the clock icon with dotted circle around, you will then find the settings to adjust photo color, lighting and B&W parameters. Tap the down arrow icon, and a menu of individual tools will show up. they allow you make precise adjustments of intensity, neutrals, tone, grain.