Annotating

An annotation is a metadata (e.g. a comment, explanation, presentational markup) attached to text, image, or other data. Often, annotations make reference to a specific part of the original data.   https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&es_th=1&ie=UTF-8#q=annotate

Within the text or on clear sticky notes, you can use the following tools and techniques for note-taking:	In the margins or on sticky notes, you can write the following information:
Underline Highlight Number Color Stars or other icons →	Notes Thoughts Summaries and paraphrases Agreements or disagreements Definitions Explanations

from  http://www.texasgateway.org/resource/annotating-deepen-understanding-english-iii-reading

Examples of annotation: