Add links in Notes on Mac
You can add links to your notes, then use them to quickly access webpages or content in other apps.
Add URL links
In the Notes app
on your Mac, click a note in the notes list or double-click a note in gallery view, then choose Edit > Substitutions > Smart Links (a tick shows it’s on).Do one of the following:
Type or paste a URL, then press the Space bar or the Return key. The URL becomes a link automatically.
Click anywhere in the note, then choose Edit > Add Link (or press Command-K). Type or paste the URL in the dialogue that appears, then click OK.
Tip: To change some text that’s already in the note into a link, first select the text, then choose Edit > Add Link.
To edit, remove, or open a link, Control-click the link, then choose an option.
Add links to an app
You can add a link to content in supported apps, like a web page in Safari, a book in Books or an episode in Podcasts.
Make sure the app you want to link to is open and active. For example, open a web page in Safari or start playing a podcast episode.
In the Notes app
on your Mac, open a note, then click the Link button 
in the toolbar.Click Add Link.
If you add a link to a Quick Note, a thumbnail of the Quick Note appears in the corner of the screen when you return to the linked content in the app.
Change the colour of links
You can change the colour of links and highlights by changing the accent colour and highlight colour in Appearance settings on your Mac. (Changes you make there apply to links and highlights in all apps.) See Change Appearance settings on Mac.