To enable commenting on your WordPress website, you should go here: http://www.mydomain.com/wp-admin/options-discussion.php to change the discussion options (to turn commenting abilities on or off) on your WordPress website.

wordpress default article settings allow people to comment

 

Also, you can check the checkbox beside “E-mail me whenever” that says “Anyone posts a comment”. You will get a notification if someone writes a comment on your blog post.

email me wordpress comment options

Then, go to an old post you’ve already published, and click the “edit” link. In the top/right of the WordPress dashboard screen you will see “Screen Options”.

click the screen options button in wp admin

 

Make sure the “Discussion” checkbox is checked.

screen options in wordpress admin panel open

Then, at the bottom of the post edit page, there will be a checkbox that says “Allow comments.” You should check that if you want that post to allow comments to be made on it.

in the post edit page check allow comments

Also see Submenu Sidebars
Admin Panel Tutorial – Media
Admin Panel Tutorial – Pages
A Tour of the WordPress Admin Panel