Yep there are 2 ways to do this
1) you can turn these off globally in Settings / discussion. This will turn it off for new posts.
2) You can turn them off for individual pages and posts (that you have already published) by… going to the edit screen of the post, then clicking on screen options (look top right), then ticking discussion. Then scroll down beneath the post and unclick allow comments.
Let me know if that works for you,