"Ella les manda regalos a sus abuelos."
Translation:She sends gifts to her grandparents.
The people receiving the gifts are the indirect object of the sentence. Spanish uses the indirect object pronoun (here les) even if there is an "a-phrase" explaining who the receivers are (a sus abuelos).
Ella les manda regalos = She sends gifts to them.
Ella les manda regalos a sus abuelos = She sends gifts to her grandparents. This sentence contains more information. The les is still there, but now it's untranslated in the English sentence.
i thought bandar meant to order. i had she ordered gifts.....................