A couple of quick questions

I've been meaning to ask this for a long while

Is there a way of exporting or copying a DataFolder from one experiemnt to another?

Is there a default setting to set a frame around all graphs?

To copy files/folders use the "Browse Expt..." button on the data browser.  Clicking on that will open an OS file explorer window from which you can select and experiment to "browse".  Selecting an Igor experiment will add a view of the folders in that experiment to the browser window from which you can drag/drop files or folder to the open experiment.  It's one way... you can only copy files from the "browsed" experiment to the open one.

Execute displayhelptopic "Browsing Experiments" on the command line for more info.

Your second question: Create a graph and design it how you would like to look. Go to Graph => Capture Graph Prefs and check all the settings you would like to keep. From there on all new graphs will honor these settings. So go ahead and create a graph with a "frame" (= enable mirror axis on both left and top without ticks) and save this style.

If you want a programmatic way to save/load a data folder contents, use the operations SaveData and LoadData. The LoadData operation is the engine for the Data Browser's Browse Experiment functionality.

The frame you mention is not saved in preferences. It was actually an accident that it works in a top-level graph at all. It was originally conceived for use framing a subwindow graph. It seemed arbitrary to prohibit its use for top-level graphs, so we kept it.

You can save a style macro- ModifyGraph frameStyle and frameInset keywords are saved in style macros.