Please let me know how can create a workflow in onedrive for business?
Is there a tool like SharePoint designer to create a workflow?
You cannot create Workflow for Onedrive but if you want workflow like functionality then you can try Microsoft Flow. There are various triggers/events which you can define for initiating your Flow (seen in screenshot below)
you can start creating flow by logging in to https://flow.microsoft.com/
to learn basics you can visit https://flow.microsoft.com/en-us/documentation/getting-started/