An Intent is used as part of a migration plan to tell cloudstep what you want to do with an Application as part of your plan. There are several different Intents and they have different impacts on your model. Intents can also show the starting point for an application.
This indicates that an Applicatio is currently deployed on servers on-premises. Generally you would not model migrating to an on-premises Intent. If you plan to leave the application on-premises simply don't add it to the plan and it will stay as it is.
This intent means that you plan to operate the application as Infrastructure as a Service in a similar way to how it is currently operated. If an application has a starting point Intent of "On-Premises" then all the servers will be migrated to IaaS according to your plan.
This intent means that you intend to operate the application as Software as a Service. This means that there is no infrastructure component, only a subscription fee. If the current state is On-Premises or IaaS then any servers will be removed from the model in that Scenario.
An Intent of retire means that any infrastructure and costs associated with the application going forward will stop. It is similar to a Tombstone but for an application.