Writing a sentence in past tense in French

Question

I read the following sentence in French:

Le Parlement a modifié la loi.

Does the above sentence mean?

The parlement changed the law

In this case, cannot we write the above sentence as:

Le Parlement modifié la loi.

In other words, why is to included here?

Answer 1

Does the above sentence mean?

"The parlement changed the law"

Yes, this is the right translation.

In other words, why is to included here?

You're mistaken on the use of "a". It's not used as "to" (à) but as the verb "to have".

Avoir modifié la loi. Passé composé avec l'auxilière avoir. Voir ici pour la conjugaison complète.