Based on whether verbs express facts, commands, questions, emotions, desires, or conditions, they are categorized into various groups.

Declarative mood describes the type of sentence that makes a statement or declaration or provides information about something. Sentences in declarative mood typically begin with a subject followed by a verb, and verb complements, if necessary. However, sometimes the normal word order might be altered for emphasis or stylistic purposes.
Declarative sentences can be affirmative or negative. For example:

The imperative mood is used to give orders, commands, or instructions. This mood is formed using the main verb in the imperative form, which is typically the bare infinitive (i.e., the infinitive without 'to') used at the beginning of a sentence.
Imperative verbs are categorized into two groups based on whether the command is to do or not to do the action:

To form a negative command in the imperative mood, the auxiliary verb 'do' is followed by the negative marker 'not' before the bare infinitive.

The imperative mood usually does not include a subject at the beginning, but the subject is implied to be the pronoun 'you' that might sometimes be explicitly stated.

'The interrogative mood' is used to ask questions. In other words, an interrogative sentence is a sentence that seeks information or clarification. There are two main types of interrogative sentences in English:

Questions are marked by inversion of the subject and auxiliary, although there are some exceptions to this general rule. Another distinguishing characteristic of interrogatives is the use of a question mark at the end of sentences. Take a look at some examples:

The exclamatory mood describes a strong emotion such as excitement, admiration, fear, anger, or any other intense feeling. Exclamatory mood is marked by the use of exclamation mark at the end of the sentence. Any verb can be used in exclamatory sentences but many of these sentences are distinguished by the use of 'what' or 'how' at the beginning.

The subjunctive mood is used to describe situations that are hypothetical, contrary to fact, or uncertain, unlike the declarative mood. It is often used to express wishes, opinions, obligations, suggestions, and other non-factual scenarios. The key feature of the subjunctive mood is that it is used to refer to events that may not have occurred yet or are unlikely to occur.

The subjunctive mood is always expressed by a dependent clause and is marked by special verb forms. In present subjunctive clauses, the verb is always in its base form, while in the past subjunctive clauses the verb is always in past simple form, although not actually referring to a past time.

The conditional mood is used to express events or actions that are dependent on a certain condition or circumstance, and may or may not happen. It is often used to express a hypothetical situation, a possibility, or a conjecture.

There are five types of conditional moods in English:

Zero conditionals express a general truth or fact, and imply that a particular action or result will always follow a certain condition.
The zero conditional is typically formed using the present simple tense in both clauses of the sentence, with words like 'if' or 'when' introducing the condition. For example:

The first conditional refers to a future event that is likely to happen if a specific condition is met. The condition clause expresses this condition, and is often introduced with a condition marker like 'if'. The first conditional uses the present simple tense in the condition clause and a future simple tense in the result clause. Check out the examples:

The second conditional refers to a hypothetical situation that is unlikely or impossible to happen in the present or future. It is often used to express a situation that could have happened differently, or to make a suggestion, or express a wish that is unlikely to be fulfilled. The second conditional is usually formed using the past simple tense in the condition clause and the modal verb 'would' followed by the base form of the verb in the main clause. Here are some examples:

The third conditional refers to a hypothetical situation or event that did not happen in the past, and is used to express a regret or a missed opportunity. It is often used to imagine what could have happened differently in the past if circumstances had been different.
The third conditional is usually formed using the past perfect tense in the condition clause and the modal verb 'would have' followed by a past participle in the main clause. Here are some examples.

The mixed conditional is a type of conditional sentence that combines elements of the second and third conditional moods. It is used to express a hypothetical or unreal situation in the present or future that is linked to a past event or condition. In a mixed conditional sentence, one clause typically uses the past perfect tense, while the other clause uses 'would' + base form of the verb. Another possible structure consists of past simple tense in the condition clause and 'would have' followed by the past participle in the result clause. Here are the examples: