1-People say Omar studies hard.(passive)

[abo.omar]

Make passive
1-People say Omar studies hard.
2-People say Omar studied hard.
The answers
1- Omar is said to study hard.
2-Omar is said to have studied hard.
Are these answers correct?

[Tarheel]

If you are asking if the second set of sentences are in the passive voice, yes. Another possibility:

Omar is known for working hard at his studies.

(I wouldn't call them answers unless they are answers to test questions.)

[jutfrank]

Yes, they're correct.

[emsr2d2]

If you are asking if the second set of sentences are in the passive voice, yes. Another possibility:

Omar is known for working hard at his studies.

(I wouldn't call them answers unless they are answers to test questions.)

I believe the OP called them answers because it appears to be an exercise. The top line instructs the student to put those two sentences into the passive. The OP then gives his suggested answers.

[abo.omar]

If you are asking if the second set of sentences are in the passive voice, yes. Another possibility:

Omar is known for working hard at his studies.

(I wouldn't call them answers unless they are answers to test questions.) Yes, it is.

Another possibility:
It is said that Omar studies hard. It is said that Omar studied hard.

[abo.omar]

Yes, they're correct.

So we can say the structure is to followed by the infinitive in the present passive form.
So we can say the structure is to have followed by the p.p in the past passive form.

[GoesStation]

So we can say the structure is to followed by the infinitive in the present passive form.
So we can say the structure is to have followed by the p.p in the past passive form.

No. You can say the structure is "to" followed by the infinitive and "to have" followed by the past participle in the respective forms. Quotation marks are required punctuation.

[Tdol]

Another possibility:
It is said that Omar studies hard. It is said that Omar studied hard.

Has Omar stopped studying?

[abo.omar]

Has Omar stopped studying?

It is in present simple tense which means it is his habit to study hard.