We have a beautiful sacrament called matrimony. It is a sacrament which most of the faithful receive in their lives. As you know the man and woman pledge love and fidelity to each other for the rest of their lives. They also answer the question of the minister to be open to the possibility of children and to bring them up according to the law of Christ and His Church.
Every Catholic is obligated by the Catholic Church to have their wedding in the Catholic Church by a deacon/priest, if they want their marriage blessed by the Church and considered a valid sacrament. There are exceptions, but only with the permission and blessing of the Church. If they do not follow the law of the Church, then the Church does not consider them sacramentally married.
On the other side of the coin, if two Christians (non-Catholics) who are baptized get married, no matter where, and it is their first marriage for each of them, then they are sacramentally married according to the Catholic Church. It has the same validity as two Catholics with a priest. Of course, you know that the Catholic Church has only weddings of a man and woman.
I know that Pope Francis has expressed a different opinion, but it has not become the law of the Church.
Please pray for those who desire the sacrament but are not able to receive it at this moment.