I am trying to build a workflow to iterate through a list based on IDs. I found this great PDF/Tutorial, but, of course, it's not for Office 365 and the actions look so different I have no idea what to use for "Call Web service" here:
I am trying to follow the PDF which is attached on this post: How to design a workflow that cycles through all items within a list
This is what's in the PDF (left) versus what I see in O365:
Can I ask what you're trying to do with this action? It looks like from the image that the example was using the Nintex On-Premises API to start a workflow on a list item? If this is the case there is actually an action you may be able to use called Start Workflow which should allow you to start a workflow on any items (assuming that in the Query List you are collecting some List IDs to start on).
Just another note, if it is for starting workflows, there are limits in place by Microsoft that limit the number of simultaneous workflows instances you can activate at the same time, so this is not a great pattern to use if you are trying to start 1000's of workflows.