You can offer it for any intention that you believe is in line with God’s will. You can offer it for one person, or for many people, or for all people (e.g., “for the salvation of souls”). You can offer it for the souls in purgatory — for individual souls or family groups or for all of them. You can offer it for the end to abortion, the holiness of marriages and families, or any other issue that concerns you. You can offer it for “all the intentions of the Blessed Virgin Mary,” and you’re pretty much covering every good intention. The merits of Christ’s passion, death, and resurrection — which are made present at every Mass — are infinite, so don’t be afraid to ask for whatever comes to mind. Just pray as the Holy Spirit leads you.