You really should read up on page setups, and using the publish to pdf function.
If you insist on using the exportpdf command, this is what you need to do:
Make sure your drawing is set up to the correct size, A3 or A4. It's a good idea to have these small angles that defines the edges of the paper. That way, plotting "extents" will give the perfect result.

Run the EXPORTPDF command, and set Export to Extents. This makes sure that everything in your drawing is put in the sheet.
Set page setup to override and click the Page Setup Override button.

For plot style table, select acad.ctb for color, and monochrome.ctb for black and white. If your drwing template is correctly set up, you can use 1:1 for scale. If not, use Scale to fit.

Now, when you create you PDF, you should get the result you want:

But, you REALLY should read up on page setups, and have some predefined page setups in your drawing template. One for B&W and one for color, one for this printer, and one for that printer.
That way it would be really easy or you to use the plot project and publish to pdf functions.
Trond Hasse LieEPLAN Expert and ex-AutoCAD Electrical user.
Autodesk Expert Elite Alumni
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