A Master/Mistress is a specific kind of Dominant. They are more likely to take on a 24/7 relationship with their submissive/slave and control all aspects of their sub’s life. There may be exceptions, for example when the partners are at work, otherwise a Master/Mistress is in control all of the time.
They will train their slaves to serve them in the way they enjoy. This will include domestic chores and service as well as sexual and kink aspects of their lives. Some expect their slaves to ask permission to eat, use the bathroom and other mundane acts, taking control of everything their submissive does.
Of course, all this is pre-agreed. It may all be written down in a formal contract or may have been discussed in advance. There will be ways for the slave to express discomfort and to say no when they don’t want to do something. This could be in the forum of a safeword or something else that is pre-agreed. Even though the relationship seems very one-sided, it is consensual. A Master/Mistress has their slave’s well-being at heart and will never make them do anything that is unsafe or they won’t like, that is part of the nature of the trust and control between them.