Declaration of the National Anti-Slavery Convention was written by William Lloyd Garrison for the formation of the American Anti-Slavery Society in December 1833. It was reprinted in The Liberator on December 14, 1833. It is now available in the Public Domain.
You can also use the Optimized PDF option to crank the size down in very targeted ways. Given the big before/after shift, the culprit is probably the image you're embedding. Try exporting that file in various formats (PDF, jpg, png) and then import it.
Clicking this button to browse and open your PDF file in it. Step 2. Choose Output Format With the document uploaded, you will see various conversion buttons along the Home tab. Select To Other at the end of the column, and choose Convert to HWP from the drop-down menu. Step 3. Convert Files to HWP In the new dialog, you can set the output folder where to save the converted .hwp format file in your local drive.