As far as I know, a Catholic marriage must take place in a Catholic church unless approved by the bishop, so absolutely the bishop would have to know about this because you will need his permission.
I believe that’s true for a Catholic-Catholic marriage.
On interfaith marriages (I’ve only attended one in a hotel hallway) it was enough to have a Catholic priest present.
For a Catholic to marry a non-catholic requires the permission of the Bishop of the Catholic, and if the non-catholic is of an Apostolic faith, theirs as well. It’s seldom hard to obtain.
Can. 1115 Marriages are to be celebrated in a parish where either of the contracting parties has a domicile, quasidomicile, or month long residence or, if it concerns transients, in the parish where they actually reside. With the permission of the proper ordinary or proper pastor, marriages can be celebrated elsewhere.
Can. 1124 Without express permission of the competent authority, a marriage is prohibited between two baptized persons of whom one is baptized in the Catholic Church or received into it after baptism and has not defected from it by a formal act and the other of whom is enrolled in a Church or ecclesial community not in full communion with the Catholic Church.
Can. 1125 The local ordinary can grant a permission of this kind if there is a just and reasonable cause. He is not to grant it unless the following conditions have been fulfilled:
1/ the Catholic party is to declare that he or she is prepared to remove dangers of defecting from the faith and is to make a sincere promise to do all in his or her power so that all offspring are baptized and brought up in the Catholic Church;
2/ the other party is to be informed at an appropriate time about the promises which the Catholic party is to make, in such a way that it is certain that he or she is truly aware of the promise and obligation of the Catholic party;
3/ both parties are to be instructed about the purposes and essential properties of marriage which neither of the contracting parties is to exclude.
vatican.va/archive/ENG1104/__P41.HTM