Four different menu options for saving documents:
Choose File > Save Document to save the document in the active window. If it's a newly created document, then you will be presented with a Save As dialog box, enabling you to type in a filename and select a folder.
Choose File > Save Document As to save the document in the active window with a new filename and/or folder location. You will be presented with a Save As dialog box, to type in a filename and select a folder. The active window will switch to editing this newly saved copy.
Choose File > Save Document Copy As to save a copy of the document in the active window with a new filename and/or folder location. You will be presented with a Save As dialog box, to type in a filename and select a folder. The active window will remain editing the original copy.
Choose File > Save All to save all open documents.