Present Perfect Tense

Present perfect tense describes an action that happened at an indefinite time in the past or that began in the past and continues in the present.This tense is formed by using has/have with the past participle of the verb. Most past participles end in -ed. Irregular verbs have special past participles that must be memorized.

Example
Meaning

The researchers have traveled to many countries in order to collect more significant data.
At an indefinite time

Women have voted in presidential elections since 1921.
Continues in the present

Past Perfect Tense
Past perfect tense describes an action that took place in the past before another past action. This tense is formed by using had with the past participle of the verb.

By the time the troops arrived, the war had ended.

Future Perfect Tense

Future perfect tense describes an action that will occur in the future before some other action. This tense is formed by using will have with the past participle of the verb.
By the time the troops arrive, the combat group will have spent several weeks waiting.

Perfect Progressive Forms
Present Perfect Progressive
Present perfect progressive tense describes an action that began in the past, continues in the present, and may continue into the future. This tense is formed by using has/have been and the present participle of the verb (the verb form ending in -ing).
The CEO has been considering a transfer to the state of Texas where profits would be larger.
Past Perfect Progressive

Past perfect progressive tense describes a past, ongoing action that was completed before some other past action. This tense is formed by using had been and the present perfect of the verb (the verb form ending in -ing).

Before the budget cuts, the students had been participating in many extracurricular activities.

Future Perfect Progressive

Future perfect progressive tense describes a future, ongoing action that will occur before some specified future time. This tense is formed by using will have been and the present participle of the verb (the verb form ending in -ing).

By the year 2020, linguists will have been studying and defining the Indo-European language family for more than 200 years.