I want to moderate the content by visitors on my Facebook Page

If you're an admin of a Page, you can block certain words from appearing on your Page and turn on the profanity filter.

 

Blocking Words

When people include a word you've blocked in a post or comment on your Page, it won't appear on your Page. To block words:

1. Click Settings at the top of your Page.
2. From General, click Page Moderation.
3. Type the words you want to block, separated by commas. You'll need to add both the singular and plural forms of the word you want to block.
4. Click Save Changes.

You can unhide comments that contain blocked words by going to the comment and clicking Unhide.

Profanity Filter

You can block different degrees of profanity from appearing on your Page. Facebook determine what to block by using the most commonly reported words and phrases marked offensive by the community. 

To turn on the profanity filter:

1. Click Settings at the top of your Page.
2. From General, click Profanity Filter.
3. Select Medium or Strong.
4. Click Save Changes.