Journaling in your heritage album should include names and dates. And THE STORY, if you know it.
Be sure to use acid-free pens and markers.
I’ve seen some very creative ways to tell THE STORY in scrapbooks, especially if you don’t wish to tear your audience away from the focus of the page which, of course, should be the photograph of your ancestor. Some write down the story on the back of the background page, some write the story on a card and slip it down into a small envelope fastened to the background or fashion tiny numbered file folders that flip open. Some add the important stuff to tags and attach it in some fashion to the page like with tiny brads or through an eyelet. I’ve seen extra pages fastened accordian style into the page spread ditch with THE STORY written inside each page.
Your descendants won’t know THE STORIES unless you tell them.