How to change photo create date back to exif create date, esp. when export from Photo App in Mac OS

Lately I need to touch up photo in the Photo App on my Mac. Yet, after I export the edited photos, I found that all the create date became the date I export the photo instead of the date I took the photo. After some googling and I found a free tool call exiftool which can help change the create date to the create date in exif. The instructions are as follow

1. download exiftool from https://exiftool.org/ , I got the mac package which is a dmg file

2. go to the folder where you have export the photos from Photo App

3. right click the folder and choose "New Terminal at Folder"

4. Type/Copy and Paste the line below to the terminal and hit enter and wait the prompt to tell the process finished

exiftool -r '-FileModifyDate<DateTimeOriginal' *