New Post: How to use closed xml to create excel file ?

1) Yes. the open xml sdk 2.0 needs to either be installed on the system where you test or deploy your application, or it needs to be referenced as part of the project and marked as Copy Local = True
2) ClosedXML should be referenced in your project and marked as Copy Local = True. You can put the closedxml.dll as part of the project area or elsewhere as long as it is referenced and marked Copy Local = True which will make it part of the delivered code set.