Multiple remote tower operations means a single controller working position provides air traffic services to more than one airport. This is one of the most operationally and politically sensitive capabilities in the field, and it is not a default.
Two distinct modes exist, approved separately: sequential operation, where a position handles one airport at a time and switches between them, and simultaneous operation, where a position handles more than one airport at once. Simultaneous operation carries substantially higher workload and safety scrutiny.
Nothing here should imply a controller can casually work several airports. Each mode and each airport pairing is safety-assessed, and operational acceptance depends on regulator approval, procedures, staffing, training, and local context.