The present perfect simple can be used:
•To talk about a finished past action without mentioning when it occurred
👉 I have seen Game of Thrones (we don’t know when)
•To talk about an action that started in the past and continues in the present
👉 She has worked in this office for two years (and still is working there)
•To talk about experiences in someone’s life
👉 They have visited a lot of countries (in their lives)
To form sentences in the present perfect we follow these rules:
•Affirmative sentences → have / has + past participle or contractions ‘ve / ‘s + past participle
👉 I have gone to London
👉 They‘ve lived here all their lives
•Negative sentences → have / has + not + past participle or contractions haven’t / hasn’t + past participle
👉 He has not worked in his project
👉 You haven’t eaten yet!
•Questions → Have / Has + subject + past participle ?
👉 Has he prepared for the exam?
👉 Have we learnt anything at all?