It is possible to include the same text box content in several blocks, and these blocks can appear on different pages. Updating the text in one block will also change it in all other pages in which it appears. You can see a list of all the pages on which a particular note is contained in your notes area under the "Content" menu.
When you are editing a group or institution page, remember that other group or institution members may have inserted this text inside their own pages. If you edit it here, it will be updated on their pages too.
You can also make a copy of the selected note and then when you edit it, the changes will only affect this page.