Ans 1: (Master Answer)
Present Perfect Tense indicates an action that has either occurred in the past or began in the past and continued to the present time. Example- Soni has lived here all her life.
Future Perfect Tense indicates an action will have been completed at some point in the future. Example- Ram will have completed his assignment by tommorow.
Past Perfect Tense indicates that an action was completed at some point in the past before something else happened. Example- I had walked two miles by lunchtime.