I assume you are asking how pass some value to your pulumi code to drive behavior. There are basically two options:
• Pulumi configuration: This allows you to define stack-specific values that can be consumed by your pulumi program. See:
https://www.pulumi.com/docs/intro/concepts/config/ this includes strong support for secrets (see
https://www.pulumi.com/docs/intro/concepts/secrets/)
• Environment variables: You can set environment variables that your code can then read using whatever method your language of choice supports.