You can enter Photo Mode from the pause menu while in-game.
You can move the camera freely to find the best angle for your shot and make it unique using the available customisations:
Filters - Chromatic Aberration, Film Grain, Filter, Filter Intensity
Remember to press the Toggle UI button to hide the interface before taking the picture!
Press Space to save the snapshot.
The default save location is: C:\Users\%username%\Documents\My Games\Far Cry New Dawn\Screenshots.
Check out Microsoft's Record and Capture instructions.
Take a look at Sony's Screenshot guide.
Please note that there may be specific moments, such as in the middle of certain animations, Photo Mode will be unavailable.