Every time you create a document in NextGen, it pulls a file and inserts it into the header, and pulls another file and inserts it into the footer.
Of course the default is the header includes a NextGen logo image, and the footer includes NextGen’s address.
One of the first things you will want to do is get rid of this stuff and setup your documents with your own brand.
In the EHR, you can click tools -> document builder.
A window pops up and there is a file folder called Sub_documents. browse these files to find both the sub_footer.NGN file or the sub_header.NGN file. Edit and Save these two documents to include the new information in all your new documents.