It is not possible to share multiple notes directly within Google Keep.
It is however possible to export multiple notes into one Google Doc file, where they then can be shared.
To share all notes of one label via Google Docs, follow these steps:
Select the label you want to share
Select all notes (cmd-a)
Choose "More" (the three vertical dots at ...
You can write keep.new to create a new note. Make sure that:
You are logged in with your Google Account
You are online
You can even use these other links:
doc.new / sheet.new / slide.new to create a new Google Document / Spreadsheet / Slide;
cal.new to create a new Google Calendar event...
Explore all the .new shortcuts on whats.new