Have done is the present perfect tense. The simple present tense is do.
For example:
I have done my homework becomes I do my homework.
You could also switch to the present continuous tense:
I have done my homework becomes I am doing my homework.
Or the present perfect continuous tense:
I have done my homework becomes I have been doing my homework.
The present tense of "done" is "do."
The present tense of "have done" is "do."
The present tense of "change" is "changes."
Did is the past tense of do. Have done is present perfect.
Past tense is a tense that was already done, or it takes the plural form. Present tense is a tense that was a singular.
To change a verb from present tense to past tense, usually you add "-ed" to the end of the verb. For example, "to have" in present tense becomes "had" in past tense.
Using the verb 'do': Simple past tense: did Present perfect tense: I/You/We/They have done. He/She/It has done.
"has done" is present perfect.
He has done.
He has done.
Do is the present tense. The past tense is did. The past participle is done.
He is.