Haptic Touch or 3D Touch

You can employ Haptic Touch (or 3D Touch on older iPhones) to sneakily read an iMessage without alerting the sender. Begin by finding the conversation you wish to peruse in the Messages app. Then, press and hold the conversation thread until a preview of the message appears.

Usually, unless the message is particularly long, you should be able to read the complete text using Haptic or 3D Touch without triggering read receipts. However, exercise caution not to inadvertently tap your screen while reading, as this could activate read receipts, thereby defeating the purpose of this method in the first place.

This technique offers a discreet way to check your messages, especially if you want to keep your reading activity private. It's a handy workaround to maintain your read status incognito, ensuring that the sender remains unaware that you've read their message.