Dictate instead of typing

Turn it on in System Settings → Keyboard, in the Dictation section. From then on, put the cursor in a text field and press the Microphone key in the top row of the keyboard, if yours has one, or the Dictation shortcut chosen in that same section.

Then just speak. In supported languages Dictation inserts commas, full stops and question marks by itself; if you would rather say them, you can turn that off in the same settings.

The same section also tells you whether your voice input is processed on the Mac itself rather than sent to Apple’s servers — worth checking if you dictate anything private.