So, you've heard about the new notes object in SalesForce and you want to start using it. What I've found is that it's very useful, however, it kind of disappeared on me with the new lightning experience of SalesForce. Here I'll show you how to enable it, then we'll add to the forms so we can really start using it.
First, enable the object itself by going to Setup, then search for "note" in the search area (I always do this as it's so much easier to use to find the items). Look for "Notes Settings". Here you're going to enable the "enhanced notes", then save it.
Next, we have to add the "notes" related list to the right forms. We'll do the account form here but you can do it for any object. Please note, this is very different from the "notes and attachments" area of the form. Once the new enhanced notes are enabled, you'll see that the old way of adding notes is now gone from that related list and you can only add attachments.
In the image above, you can see that I have "Notes" as it's own related list on this form. To add that, open any account, then click "Edit Layout" in the upper right.
Now, add the related list by clicking on the related list area (on the left), then drag the "Notes" related list to the form.
This will add it to the list. Save the form and you're ready to start using.....