Plus on Setapp is an AI assistant application that helps you write, translate, summarize, and explain text. It can select text within any application and send it to the AI assistant with a simple shortcut key, allowing it to improve, proofread, summarize, explain, or translate your text. You can also customize prompts to accomplish specific tasks. Plus on Setapp is part of the Setapp subscription service, which costs $9.99/month.