If you find the macOS screenshot function too limited, here is a small utility that enriches it with some very practical options: Shottr. This allows you to perform many actions in addition to the native options. For example, we can quickly add an arrow to highlight an element, or even pixelate certain private data.
The software is full of handy little features. An OCR module is present to quickly copy the text displayed on an image, and an eyedropper tool allows you to obtain the code of a color in different formats (hexadecimal, CSS rgba, RGB, etc.). It is also possible to take a screenshot of a long window, even if it is not entirely visible on the screen: perfect for taking a screen of a spreading web page or a discussion.
A well-thought-out “Eraser” function allows you to erase certain parts of the image, which will be intelligently replaced by a background of the same color to avoid having large empty squares on your screenshot. The arrow keys offer access to a ruler to know the distance in pixels between several elements. An automatic selection tool is accessible by CMD + Click, in order for example to quickly copy an element. We can also add text bubbles, but unfortunately the font and size are not really customizable.

The software is powerful and quite easy to learn, even if its package of features may put off some people. Note that an icon is permanently displayed in the menu bar and that the keyboard shortcuts can be configured. Shottr is currently completely free: it’s worth downloading it to try. The application weighs 1.5 MB, is optimized for M1 Macs and is available from macOS Catalina.