§1. The Most Holy Eucharist: 1/ must be reserved in the cathedral church or its equivalent, in every parish church, and in a church or oratory connected to the house of a religious institute or society of apostolic life; 2/ can be reserved in the chapel of the bishop and, with the permission of the local ordinary, in other churches, oratories, and chapels.
§2. In sacred places where the Most Holy Eucharist is reserved, there must always be someone responsible for it and, insofar as possible, a priest is to celebrate Mass there at least twice a month.
Source: Code of Canon Law (Vatican.va)