Hi @kaitlin23131538zxrr,
Sorry about Photomerge not working for you. It sounds like you're using an older version of Photoshop with a newer version of macOS which may not always be the most compatible configuration.
Have you tried Photomerge with Photoshop 23.x?
You can install 23.x and uncheck "remove old versions" while doing to so to retain your 19.x version of Photoshop on your system.
Give that a try and let us know if Photomerge is working for you there.
Regards,
Pete