What is a foreign filing?
Insights 
Michael Moradzadeh · August 19, 2009
Whenever a corporation or limited liability company does business (i.e. enters contracts or agreements) in a state other than the state in which they are domiciled, they are required to do a foreign filing in that state. For example, if a business is incorporated in Delaware, but has an office and/or employees based in California, that business needs to do a foreign filing in California. In such a situation the corporation will need to pay franchise taxes in both Delaware and California.