Visit the developer page and create a new app at https://my.freshbooks.com/#/developer
Make sure to include the name of the application and redirect URI in the application form.

The name of the application has to be unique as it will be used to display on the FreshBooks app store and on a FreshBooks user’s integrations page once they have connected with your application.  

The redirect URI should be an endpoint in your application that will receive the authorization code and will use it to retrieve the bearer token and refresh token.

These will be necessary to make authenticated calls to the FreshBooks API. To get more information on our authentication process visit our Oauth documentation.
Save your application.

Get your Client ID and Client Secret from your app page at the bottom. Fill in these details in the Plugins tab on Bubble.io.

Demo: https://ncv-demos3.bubbleapps.io/version-test/freshbooks

Editor: https://bubble.io/page?type=page&name=freshbooks&id=ncv-demos3&test_plugin=1671479825772x491271499589091300_current&tab=tabs-1