Yes! Autocorrect is currently available in the Grammarly browser extension.
You can switch autocorrect on or off by clicking the G icon in your browser’s toolbar and toggling the switch next to Correct spelling automatically:
Alternatively, you can click the G icon in the text field, select the gear icon, and toggle the switch next to Correct spelling automatically:
Once Grammarly has corrected a certain word, a gray dotted line appears under it. To see what changed, hover over the underlined word in question: