How do I remove comments from my pages or posts?

Enabling/disabling comments is a core WordPress option and you can disable these a couple ways.

The easiest way to go to your Edit page screen that lists all of your pages. Hover over a page title and select Quick Edit and you'll be able to uncheck the Allow Comments checkbox. Then be sure to Update your changes.

You can also select all pages using the checkboxes on the left side of the page and do a Bulk Edit (drop down at the top) and disable all comments at once.

The third option is to go into each page separately, select the Screen Options tab at the top and enable the Comments and Discussion metaboxes. Then you'll see an option within those newly displayed metaboxes to disable the comments.