I'm spending the day making up time on my AWS certification. One challenge of an architect is having a mental model of how to build a strategy and implement a cloud migration. The framework depends on analyzing the migration from six perspectives.
Business
Build consensus among the business for moving to the cloud. Show that moving to the Cloud will gain business agility. Business leaders will have access to compute, storage, analytics, continuous integration resources from small to large scale. They will be able to provision systems in single sprints rather than over months-long provisioning cycles.
Other benefits
Consolidate data centers
Scale globally
Reduce infrastructure sprawl
Avoid unnecessary costs by only paying for what you use
Increase operational resilience with multi-AZ applications
Move to a DevOps model for business agility
Strategy
Come up with a strategy for what you want to do. Classify each application as
Re-host
Re-platform - move a stand-alone database to an RDS instance
Re-factor or re-architect - move to a servless architecture for scalability and reliability
Re-purchase - buy something new - move to a new platform
Retire - mark old technology as end of life
Retain - utilize a hybrid cloud with older technology in place
Cloud Business Office
The cloud business office plans the migration
Enterprise Architecture (That's me)
Governance (me also)
Training and Readiness (bring in virtual training - CloudGuru)
Finance - build the case
Evaluate the organization and make structural changes
Automate the Process
Use https://aws.amazon.com/application-discovery/ to discover what you have. Maintain that list with automation.