Answer:

Skimming

Skimming means to read a page or handout - skip read - by reading the headings and first sentences of each paragraph or section. It usually takes three forms: Preview, Overview and Review. See skimming for more.

Scanning

Scanning differs from skimming in that you do not deal with all of the content, but search through the material for a specific purpose or a specific word (or its synonym):

finding the answer to a question

seeking an appropriate quotation reference or statement

locating names in a directory, words in a dictionary, prices in a catalogue, etc.

When you scan, you cover only as much of the content as is necessary to accomplish your purpose. See scanning for more.

In-depth reading

In-depth (or detail) reading is the most involved and essential. The purpose of this style is to understand the concepts and arguments that the text contains. It should be done after skimming the text. See in-depth reading for more.

Explanation:

https://owll.massey.ac.nz/study-skills/reading-styles.php#:~:text=There%20are%20three%20different%20styles,%2C%20and%20in%2Ddepth%20reading.