informats instruct SAS on how to read data from any input location (such as a file, an excel spreadsheet, a named pipe, or even another SAS variable, etc.) into a variable.
SAS has just two data types - character and numeric, and each informat is specific to storing the value into either a character or numeric variable. If the destination variable is a character, then the informat will begin with a
$ symbol, anything else will be a numeric informat.
Informats are very important especially when we import data from other datasets. For example, most of the times while working on real time data, we extract data from various data sources (Oracle,Mysql,Teradata etc). Every time we import data we need to specify the informat statement so SAS can read the data properly.