You can attach photos, videos, audio files, and other items to your notes. If you’re using upgraded iCloud notes, or your notes are stored on your Mac, you can also attach map locations and website previews. (If you haven’t upgraded your iCloud notes or are using a non-iCloud account, you may not be able to attach map locations.)
If your notes are in an Exchange account, you can’t attach any files, map locations, or website previews.
When you attach images or PDF documents, you can mark them up in Notes.
Note: If you attach a video, audio file, PDF, or document to a note, you can’t lock it. (Only images, sketches, maps, or web attachments can be included in a locked note.)
From the desktop: Drag a file onto the note.
From your Photos library: Choose Window > Photo Browser, find the photo or video, then drag it to the note.
Tip: To add a Photo Browser button to the toolbar so you can open it more quickly, see Customize toolbars.
From within another app, like Maps, Safari, Photos, and more: Click the Share button 
, then choose Notes.
The Share button doesn’t appear in all apps.
You can also select some text or images, Control-click your selection, then choose Share > Notes.
To change how large an image, sketch, or PDF attachment appears in a note, Control-click the attachment, then choose View as Large Images or View as Small Images.
You can view attachments from your notes in a single window, making it easy to browse them and find just the one you want. You can only view attachments from notes stored on your Mac or upgraded notes from an iCloud account.
Click the Attachments button 
, then do any of the following:
View attachments: Click the category buttons to view different kinds of attachments. To return to the list of notes, click the Attachments button again.
Note: Attachments in notes that are locked do not appear in this view, even if you have entered your password and notes are unlocked.
Preview an attachment: Select the attachment and press the Space bar.
View the note that an attachment is in: Select the attachment, then choose View > Show in Note (or use the Touch Bar).
Open an attachment in its default app: Double-click the attachment.
Save an attachment: Control-click the attachment, then choose Save Attachment.
Some attachments, such as maps and website previews, can’t be saved.
Rename an attachment: Select the attachment, choose Edit > Rename Attachment, then type a new name.
Share the attachment with another app: Select the attachment, click the Share button , then choose an app.