How Do I Make An iPhone Photo Black & White?
Photos taken on an iPhone or iPad can quickly and easily be transformed to black & white (grayscale).
Open the Photos app and navigate to the photo you would like to edit. Select the photo and then tap the "Edit" button. From here there are a couple of ways to achieve your objective.
One option is to tap on the Filters icon (it looks like three overlapping circles). Swipe through the various filters available for your photo until you see one that will turn the photo black & white.
Alternatively, you can select the Light and Color icon (it looks like a circle surrounded by tiny dots). This surfaces the Light, Color, and B&W photo editing options. Select B&W and adjust as you see fit. Once finished, close and hit Done to save your changes.