Sawm has a number of components.
Some of these components are Fard (compulsory), some are Sunnah (regular prophetic practice) and some Mustahab (preferable).

The components of Sawm are as follows:

THE FOUR FARAA’ID OF SAWM

There are four Fard requirements in Sawm which must be observed, for the Sawm to be valid. They are:

1) Making the Niyyah (intention) for fasting

2) Abstaining from eating

3) Abstaining from drinking

4) Abstaining from intimate relations