You can turn off notifications for 'Comments' and 'Good Job' in the settings.
Please refer to the following manuals to change the settings:
Set up email and app update notifications
Web browser version: https://teachme.jp/8/manuals/4554527
Mobile app: https://teachme.jp/8/manuals/3748274
Other notifications cannot be turned off in the settings.
Related:
What happens if I add a comment to a manual or step?
https://help.teachme.jp/hc/en-us/articles/900005509786
What happens when you say "Good Job"?
https://help.teachme.jp/hc/en-us/articles/4406530178585