Managing Packages with Npm - Add a License to Your package.json The license-field is where you inform users of your project what they are allowed to do with it.
Some common licenses for open source projects include MIT and BSD. http://choosealicense.com is a great resource if you want to learn more about what license could fit your project.
License information is not required. Copyright laws in most countries will give you ownership of what you create by default. However, it’s always a good practice to explicitly state what users can and can’t do.
Fill the license-field in the package.json of your Glitch project as you find suitable.