Question

i had drank a water change in paste perfect tense

Answer 1

i have drunk water is the  past perfect tense for i had drank a water

Answer 2

Past perfect tense refers to the actions which has begun in the past and finished in the past itself when another action happened.  

It is formed by , had + past form of the verb.

Hence, the above sentence in past perfect tense would be written as:

I had drunk water.

Herein, the past participle of drink is 'drunk.'