In macOS 10.13 High Sierra, Apple significantly enhanced the editing capabilities of Photos, adding tools for adjusting specific colors, fine-tuning color and contrast via curves, and even focusing an image with vignetting. But it still lacks many features found in other image editors, including applying a filter to an arbitrary portion of an image and adding text to an image. Happily, the latest version of Photos brings back a feature from iPhoto that lets you edit any image with any editor on your Mac. Just Control- or right-click a photo and choose Edit With > YourFavoriteImageEditor, and the photo opens in that app. Make your changes, and when you save, those changes are reflected in the version in Photos.
