The Present Perfect Tense

Present perfect tense is a verb form used to express an action or situation that has started in the past and has been completed at a given point in time in the past or still continues today.
Formulas Present Perfect Tense
Present perfect tense is formed with the auxiliary verb “have” or “has”, and the past participle (verb-3)​​. Have used for I, you, they, we, while has to he, she, it, and the third person singular. While past participle can be either regular or irregular verb.
This the formula for the present perfect tense positive sentences, negative, and interrogative is as follows

• Affirmative     :      Subject  +  have/has + past participle
• Negattive       :       Subject + have/has + not + past participle
• interrogative:        Have/Has + Subject +Past Participle

We use the simple present tense

• To show past actions whose time is not definetly
• Example: I have read this book
• To show a recently completed action
• Example : I just have  sent you an email
• To show an action beginning in the past and still continuing to the present
• Example: She has studied in Cirebon since April.
• To show a repeated action in the past
• Example : She has called you three times