Can I have a pipeline progress to a stage only after manual approval?
Yes. Deployment Manager supports manual tasks, please add task at an appropriate stage and assign it to the right stakeholder, who should approve it. Deployment will not proceed till the task is approved.
NOTE – The operator record for the stakeholder needs to exist on the Deployment Manager environment. If the email address is set correctly on the Operator record, then the approver will get an email notification as shown.