The aim of reading is to understand the author’s ideas, i.e. the meaning of a text. The aim of teaching reading is to teach learners to understand these ideas and take these ideas into work. 

Meaning is a key word here, form is subsidiary and is taught for linguistic students. 

Reading for pleasure (mostly long texts) is called extensive reading, reading for  developing reading skills in foreign language is called intensive reading. The latter is considered below.

There are three types of reading:

Reading for gist is aimed at understanding the main idea of the text (e.g. Read the text and say whether you agree with the author). It checks nearly 25% of understanding.

Reading for specific information is aimed at finding some special information in the text (50% understanding).

Detailed reading has a focus on deeper understanding of the text and implies 100% understanding.

There are two approaches to reading:
– bottom-up  (understanding individual words and  phrases first and then understand the whole idea ).
It is usually deployed in the grammar-translation approach;
– top-down (understanding the main idea first and then individual words and phrases).