Comments are enabled by default on posts and disabled on pages.
You disable comments on new posts you publish in the future in Settings > Discussion.
Disable Comments
You disable comments on future posts as follows:
1. Go to Settings > Discussion

2. Uncheck the box next to ‘Allow people to post comments on new articles ‘ under Default article settings.

3. Click Save Changes at the bottom of the page.
Automatically Close Comments
An alternative option to disabling comments is to automatically close comments after a certain number of days as follows:
1. Go to Settings > Discussion

2. Select ‘Automatically close comments on articles older than” and choose the number of days before comments are closed.

3. Click Save Changes at the bottom of the page.
Enable Comments
If you’ve disabled comments on posts and want to enable comments on future posts you need to:
1. Go to Settings > Discussion.
2. Check the box next to ‘Allow people to post comments on new articles ‘ under Default article settings.
3. Click Save Changes at the bottom of the page.
Enable and Disable Comments on Published Posts and Pages
Any changes to your default article settings on Settings > Discussion only apply to any posts or pages you publish in the future.
Refer to enable and disable comments on published posts and pages here.