I am a seasoned IT person especially with IBM i and Windows.  Just starting to look at moving our small network to the cloud.  Consists of a IBM i (old model 720) and Windows server 2019.  Not sure what to select especially for testing to see if the cloud meets our needs.  I need a small VLAN where my windows server can serve websites.  The IBM i is basically a data base server.  I need VPN access to network (and thereby my servers) to work with them much as I do now with my existing colocation at a local data center.  Everything can be shared and virtual.  Only 3 users for the network, and public access to websites running Apache Tomcat on Windows.  Honestly, I am very confused looking at the offerings and not sure where to start.  Suggestions?

For Windows and IBM i in IBM Cloud you would probably use a Virtual Private Cloud (VPC) to run the Windows server. Power LPARs run in a Workspace in Power Virtual Server. So you would create a VPC and a Workspace, which would each have their own network subnets and then network them together using a Transit Gateway. The VPC can also provide a site to site VPN or a client to site VPN for access. Both of these allow you to access the IBM i from on-prem.

One easy way to set this up quickly would be to use the Power Virtual Server with VPC landing zone. This will deploy the resources I mentioned along with others for file storage, NTP, DNS, cloud monitoring, etc.

One last thing on levels since you mention a model 720. Power Virtual Server has Power9 and Power10 systems in it and it only supports IBM i releases that are in support or extended support: https://www.ibm.com/support/pages/release-life-cycle. This means that the minimum currently supported version of IBM i is 7.2.