Here are a couple of simple PopClilp extensions that run a shortcut to add a new note or enter something important into today's note.

Download it here: PopClip to NotePlan Contains the popclip extensions and the shortcuts.

Popclip Add to today

I have it setup to append the "📥 Inbox:" Section of my daily note, you can change the settings in the shortcut to suit your needs.

Popclip Add a New Note

Here, popclip launches the shortcut, which prompts the user for the title of the note. I have my note saving to the "INBOX" folder of NotePlan. You can change where to save it in the shortcut.