View this video at https://macmost.com/how-to-set-up-your-iphone-to-automatically-respond-to-text-messages.html. You can use the Shortcuts app to have your iPhone respond automatically to messages. You can choose one or more recipients and when they text you they will get a response back even if your iPhone is locked. You can customize by specifying text to look for in the original message and adding things like your location in the response.