Simplified Chinese characters are one of the two commonly used forms of Chinese characters. As its name shows, it is made of characters that have in part been "simplified" from the original written form, which are called traditional Chinese characters.

History 
When the People's Republic of China was formed in 1949, the Communist Party of China under Mao Zedong wanted to help the Chinese people read and write.  Before 1949, most Chinese people could not read.  The government hoped that by using fewer strokes to write characters, along with many other changes in the education system, the Chinese language would become more standardized like Japanese.  The Empire of Japan had brought changes to the Japanese writing system during the earlier Meiji Restoration to make literacy and education more widely available to all Japanese citizens.  Mao also hoped that simplifying Chinese characters would begin to shift Chinese people away from using the character system itself and that eventually Chinese-speakers would only use a phonetic alphabet to write.

The first set of simplified Chinese characters were first put to public use in 1956. Over time, more characters became "simplified", or existing ones changed, once in 1964 and again in 1978 and 1984. Many people did not like these changes because too many characters with different meanings were merged.

In hopes of promoting phonetic writing, the CCP was also working creating a standard romanization to accurately represent the pronunciation of Standard Chinese, pinyin. It was first taught in primary schools in 1958.

Roughly 2,000 Chinese characters have been simplified.

Current use
Today, simplified Chinese characters are used throughout Mainland China. It is also taught and used in some countries in Southeast Asia, including Singapore, and Malaysia.

Since the Republic of China fled to Taiwan and became separated from the rest of China, the government there did not choose to simplify its writing system, and so it still uses the older traditional Chinese characters. The territories of Hong Kong and Macau have also kept using traditional characters, even though they are politically part of the rest of China, which switched to simplified characters.

It could not be proven that Simplified Chinese characters were able to help people with reading and writing. As places using Traditional Chinese characters did not have literacy problems, in 2009 Pan Qing-Lin, a Chinese official, suggested to stop using Simplified Chinese characters. This did not happen.

In multi-racial societies, like Singapore, students have been learning a second language for many years. Because of this, Simplified Chinese characters are welcomed by students. People who learned the simplified set had little problem changing over to the traditional set. Even to this day, there are many reasons for the need to use traditional Chinese characters, such as working in places that did not adapt the simplified Chinese characters or reading older books that have not yet been translated to Simplified Chinese characters.

Most simplified characters have far fewer strokes. For example, the traditional character 馬 has 10 strokes, while its simplified version 马 only has 3 strokes. However, there are some  simplified characters with more strokes than their traditional versions. For example, the traditional character 強 has 11 strokes, while the simplified version 强 has 12 strokes.

Simplified vs. traditional characters 
Below is a list of simplified characters next to their traditional versions.

There are several ways to simplify characters.
 Write a character or one of its radicals in its cursive form. For example, 长 is a cursive form of 長, and 话, 银, 饮, and 狗 are cursive forms of 話, 銀, 飮, and 豿 in the same order.
 Replace a traditional character with an existing character for a word that has the same pronunciation.For example, the character 面 was and still is a traditional character that means "face" or "side", but it is now also the simplified version "noodles", since both words have the same pronunciation, miàn, and has replaced the traditional character 麵.
 Replace a radical in the character using has another radical with a similar or the same pronunciation. For example, the top part of 華, pronounced huá, is replaced with 化, pronounced huà, making the simplified character 华.
 Remove a radical from the traditional character. For example, the simplified character 杀 completely removes the right half of the traditional character 殺.
Use an ancient variant of the character that a traditional character replaced. For example, the simplified character 云 replaced the traditional character 雲, which had also replaced the simplified character 云 before the 1956 simplification.

References

Chinese language
Writing systems