If the reply button is not visible for post types like "Post", "Page", etc. you should enable the "threaded (nested) comments X levels deep" option.
The option is located in the Dashboard > Settings > Discussion admin page.
Turn on this option to allow visitors to reply to other comments inline/nested.
Then from the drop-down box, select the number of X levels deep (maximum of 10 levels) you will allow for nested comments.
Please note: some themes need to be specially coded to properly display threaded comments.
We suggest using a maximum of 3 levels deep. Anything higher and the theme layouts may not work as expected.
In case you want to say thank you! 🙂
We'd really appreciate if you leave a good review on the plugin page.
This is the best way to say thank you to this project and the support team.