Android and iOS – Passwordless authentication magic link – How to pass custom parameter from app to Auth0 mail script?

Currently, we’re using Passwordless authentication with a verification code. We want to implement magic links to simplify the process for our users. We need three things to create a deep link – user e-mail, verification code, and authentication type (login/register). In the Auth0 script (script in Auth0 Dashboard, which is responsible for generating an email message) we have access to code and user e-mail address using Liquid Syntax but we don’t know how to distinguish login from the register. I suppose we need some custom parameters to indicate it. But how we can pass custom parameters from the app to Auth0 script, to use it to construct a deep link?