Where it starts
With an inventory. In the cloud assessment we record every application and service along with its dependencies and connections. That service catalogue is the basis for everything after it, and it is also the part almost nobody has in full.
The dependencies are what matter. Moving one application is easy; separating it from the database three other systems also use is not.
The cloud readiness assessment
We then check the applications for cloud fitness and assign each one of the 6 Rs: rehost, replatform, refactor, repurchase, retire, retain.
That is the actual point of the exercise. Without it a migration becomes a blanket move, and a blanket move ends in running costs for applications you could have switched off, and applications running in the cloud more expensively than they did before.
Retire is the underrated category. Every inventory turns up systems nobody needs any more that would otherwise have been migrated.
What comes out of it
A future mode of operation per application, and therefore a migration you can plan and budget rather than start and see how far you get.