How to store data remotely when working with Unity and PUN2 (Photon Unity Networking)?

Question

C++ / C#

Good afternoon everyone!
I create multiplayer in unity using PUN2. In theory, the player creates a "map" and marks an array of coordinates on it, then goes to the "room", where there should be two such maps and each one has its own array of coordinates. The bottom line is to correctly find all the coordinates marked by the enemy. To do this, I believe, it is necessary to store the data of their coordinates and the coordinates of the opponent in a repository to which each player will have access. (Again, it is assumed that the players use different devices.) How to implement this, can you tell?