In speaking English, especially informally “on the street,” we most often use only the three simple tenses: Present, Past, and Future. However in formal more professional English you are stuck: You need all 12 tenses to effectively do business and be clear.
The “Present Perfect” tense is used to describe an action which,
-began in the past and
-is continuing into the present.
If you use the simple Past tense in this situation it will be confusing. For example:
“When did you arrive in Mexico?”
“In August. So I HAVE LIVED in Mexico for 6 months and I love it.”
Translation: I arrived in August and have continued living in Mexico until now.
The Present Perfect is formed by the AUX (Auxiliary Verb) HAVE + Past Participle (LIVED).