Each of the library journal article databases have different functionalities.
To view an article without being on the Internet, you can download the article. Most articles available online can be downloaded as PDF documents.
Once the article is downloaded, the ability to highlight or take notes, would depend on the software or services on your tablet or computer.
Some database vendors/publishers (such as ProQuest) provide options to create an account and make notations or highlight articles while online, Use the HELP in each database to explore the functionality.