You’ll need to use a web browser on a computer to comment as a Facebook Page.

If you’re not signed in, type your account information into the blanks at the top-right corner of the screen, then click Sign In.;
, You can comment as a Page on any Page, including your own.

Find pages by using the search box at the top of the screen. To go to your own Page, click its name in the “Your Pages” box at the top-right corner of the screen.
It’s not possible to comment as your Page on a personal Facebook profile.
, It’s on the right side of the post, to the left of the gray arrow. A pop-up menu will appear., Your profile image on the post will change to that of your Page., Type your comment into the blank at the bottom of the post, then press ↵ Enter (PC) or ⏎ Return (Mac). Your comment will appear as though it was posted by your Page.
Go to https://www.facebook.com in a web browser.
Go to the Page on which you want to comment.Scroll to the post on which you want to comment.
Click your profile image on the post.
Select your Page.
Post your comment.
{"src": "wikihow-all_test", "title": "How to Comment As a Page on Facebook"}