Without Authorization:

Go to the cloud function tab

Select your cloud function (check box)

Click "Add members" under Permissions tab in the right side

Enter "allUsers" under "New memebers"

Select Role as "Cloud Functions -> Cloud Functions Invoker"

Save

Test your cloud function by just pasting it in the browser

With Authorization:

It's always a good practice to set authorization on your cloud functions

Note: Cloud functions throwing error with "403 Forbidden - Your client does not have permission to get URL" should be called by authorized users.

Simple test:

Click on Cloud shell(icon) terminal in the top

type - gcloud auth print-identity-token

copy the generated token

forming Authorization key to be passed while calling cloud function 4.1 Authorization: bearer generated_token

Use above Authorization key while calling your cloud function

Note:

Never make a cloud function available to allUsers