Portrait mode on Photos app

Hi boaz242,

The instructions you're seeking can be found in the Apple Support article Change the lighting of a Portrait mode photo in Photos on Mac:

"If you took a Portrait mode photo with iPhone 8 Plus or later, you can apply six studio-quality lighting effects to change the look of the photo.

1. In the Photos app  on your Mac, double-click a Portrait mode photo, then click Edit in the toolbar.
2. Select a lighting effect.

If the lighting effects appear dimmed, click Portrait under the photo to turn them on. 

• Natural: Displays the portrait as it was originally taken.
• Studio: Brightens facial features.
• Contour: Applies dramatic directional lighting.
• Stage: Applies spotlight stage lighting with a darkened background.
• Stage Mono: Changes a portrait to black and white with stage lighting.
• High-Key Mono: Changes a portrait to black and white with a white background. (Available only for Portrait mode photos taken with iPhone 11, iPhone 11 Pro, and later versions.)

3. To set the depth of focus, click Portrait in the Adjustments tools, then drag the Depth slider. 

4. If a Portrait mode photo offers a Light option, drag the Light slider to adjust the appearance of light in the portrait."

Regards.