"The matrimonial covenant, by which a man and a woman establish between themselves a partnership of the whole of life, is by its nature ordered toward the good of the spouses and the procreation and education of offspring; this covenant between baptized persons has been raised by Christ the Lord to the dignity of a sacrament” (Catechism of the Catholic Church #1601).
A baptized Catholic is required to be married “in” the Catholic Church no matter the religion of their intended spouse. If the intended spouse is not Catholic and objects to a Catholic ceremony, permission is usually granted to be married in a place other than a Catholic church; but this permission is needed, and some marriage preparation will still be required.