Explanation

Box 1: automated
Automated flows start with an event or trigger, such as an email being received. These also support a multitude of actions in the 200+ Flow connectors.
Box 2: business process
The business process flow that creates stages or screens that enforce a certain sequence of steps. It collects data from users for each step in the stage and can kick off automated workflows.
Box 3: scheduled
Scheduled flows run regular reports that are sent out to a team and summarize everything that's happened in the past week. This includes everything from simple daily scheduling to more complex scheduling like "every
3rd Monday."
Box 4: instant
An instant flow is triggered when you click a button inside of the Flow mobile app, SharePoint, Dynamics, PowerApps, or Excel that passes context directly into your flow.
Note: There are four different Flow types that you can choose from when starting out. You can create a scheduled flow, automated flow, instant flow, or a business process flow.
Reference:
https://www.avepoint.com/blog/office-365/office-365-automation/