Sentences are formed with the help of word(s). The smallest sentence is “Go” & the longest sentence could be of around 60-70 words. But one must be modest and stick to the rule of brevity for the purpose of clarity in communication.

A sentence is divided into two parts : Subject & Predicate

Subject

Subject is a part of sentence where it names (noun) about which/whom we are talking about.

Predicate

Predicate is that part of a sentence where something is being said about the name/noun (subject).

Examples:
(1) Mother loves her child.
(2) My mother loves me.

In sentence 1, mother is a subject & loves her child is a predicate. In sentence 2, my mother is subject and loves me is a predicate. Therefore, subject can be one word or group of words.

Generally, subject is placed in the beginning of a sentence ie. before the predicate, but sometimes it can be placed at the end of a sentence also ie. After the predicate.

Example:
Here comes the millioner.

In imperative sentences, the subject is silent
Example:
Come here.

(the subject ‘you’ is understood /implied-is not stated)