Mary is human, not divine. She doesn’t have the power to answer our prayers as God does. That said, she’s seen as a valuable intercessor, someone who prays for others. If we ask her to pray on our behalf, Catholics believe that she will.
Because of her close relationship to her son, many believe that her intercession is particularly effective. This belief has a precedent in Scripture, during the Wedding at Cana, when Mary brings the needs of the young couple before Jesus (see John 2: 1-12).
The National Conference of Catholic Bishops, in their 1973 letter “Behold Your Mother: Woman of Faith,” say this:
“We believe that, having Christ, we have all things together with him. However, it is part of God’s loving plan that, even as we help one another on earth by our prayers and deeds, so we can rely on the blessed in heaven, above all the Blessed Virgin Mary, to assist us by their prayers.”
Bottom line: You aren’t required to ask for Mary’s intercession. But many Catholics find comfort in the idea of a heavenly mom adding her prayers to theirs.