Office 365 - I used to have OneDrive, can I use my OneDrive App with Office 365?

Since OneDrive and OneDrive for Business are different services, you will need access to your files at either of them with its own client application.

• OneDrive is free online personal storage that you get with either a Microsoft account or Outlook.com. Use OneDrive to save documents, photos, and other files in the cloud, share them with friends, and even collaborate on content. You’re free to decide how you want to use it and it is completely managed by the individual.
  
  
• OneDrive for Business is online storage intended for business purposes and is is implemented on SharePoint. The OneDrive for Business library is managed by site administrator and lets you share and collaborate on work documents with co-workers. OneDrive for Business supports documentation features such as versioning, content approval, workflows, and check-in/check-out, etc.

The OneDrive app and the OneDrive for Business client sync application can be installed on your computer at the same time. 

The OneDrive app cannot be used to sync documents to your Office 365 and only the OneDrive for Business client sync application can achieve synchronization with OneDrive for Business. More information can be found at What is OneDrive for Business?