How can I transfer a PDF from Adobe Digital Editions to another PDF reader (e.g., Acrobat)?

[#1]

This software is functionally unusable. I paid good money for a textbook that I need to read for school and I can't even save my highlights, scroll without serious lag, or close the table of contents without the software skipping to the last page of the textbook. Can anyone help me get this textbook onto software that actually functions? Thank you in advance, you would save me a lot of stress this semester. 

[#2]

This software is functionally unusable. I paid good money for a textbook that I need to read for school and I can't even save my highlights, scroll without serious lag, or close the table of contents without the software skipping to the last page of the textbook. Can anyone help me get this textbook onto software that actually functions? Thank you in advance, you would save me a lot of stress this semester.