This video will teach you how to store sensitive values.
Codemagic has added a Global variables and secrets section to the team settings page so you can manage all your secrets in one place for your codemagic.yaml files. This means you will only have to update that expired certificate in one place, instead of all your apps.

Read more about environment variable groups from the documentation: https://docs.codemagic.io/variables/environment-variable-groups/

Get started with Codemagic: http://codemagic.io/