The Present Perfect tense is used to describe actions or events that have occurred at some point in the past but are relevant to the present. It is formed using the auxiliary verb "have" or "has" followed by the past participle of the main verb. For example, in the sentence "She has visited Paris," the action of visiting happened in the past but is connected to the present. This tense can also express experiences, changes, or situations that continue to the present. For instance, "They have lived in New York for five years" indicates that their living situation started in the past and is still ongoing.