When we talk about experience or results, we use the present perfect form

This form uses "have" followed by the participle

For regular verbs, this participle is identical to the past tense form

For irregular verbs, this participle is often different 

When we use the perfect form, the primary focus is on the subject of the sentence, not the verb

It emphasizes condition, experience or results rather than actions or events.

In these two examples, we see the contrast

The top sentence gives the condition or state of the subject and the bottom sentence expresses an event.

The top sentence describes the condition of the subject of the sentence, SHE, rather than an event

The fact that she has left the hotel is now part of her experience or state of being

The bottom sentence expresses the action or event, she left which is something she did

In general, the past tense form expresses events or acts,and the perfect form expresses experience or conditions

When we use the perfect form of the verb, we focus on the state of the subject and not an action or event

Note that the past form events at specific points or periods of time, such as last year or the past five years

These events are distanced from the speaker's point of view

The perfect form expresses the state of something from the speaker's point of view, not distanced in time

These two sentences are incorrect and confusing because they give two different points of view

Here are some sentences that use the perfect form

Some are simple such as the first one and some are complex like the last one

The last one is complex because it combines many verb forms, including the passive