How to Add an approvals to a SharePoint list (configure Approvals) 

Microsoft SharePoint is expanding Approvals to any list, allowing users to configure Approvals by going to the Automate dropdown from the command bar in SharePoint Online lists or in the Microsoft Lists app.
Approvals will be actioned and available from Microsoft Teams. Note that disabling approvals will only hide the relevant columns and in-progress approvals will still be actionable in Teams. At any time, you can manually add approvals columns back into views.
After Approvals are enabled, a user can create a list item and submit it for approval. By creating an approval request and specifying the approver, the request will appear in the Approvals app in Teams or can be approved directly within the list. Once approved, the list item status is updated.