Every member of a Latter-day Saint congregation is assigned to watch over a small number of specific households, and somebody is assigned to watch over theirs. Men are assigned in pairs through the elders quorum and women in pairs through the Relief Society, and one of each pair is often a teenager, which is how the practice trains the next generation into it. An assignment usually covers three or four families and lasts a year or more.
What the assignment requires is deliberately unspecified. Since 2018 the instruction has been to find out what a household actually needs and provide it, which may mean a monthly conversation, a lift to a hospital appointment, help moving house, a text message on a hard anniversary, or, for a family that wants to be left alone, being available and otherwise leaving them alone. Progress is discussed in a ministering interview with a quorum or Relief Society leader rather than counted, which was the point of the change.
The practice is what makes a ward function as a mutual aid organisation and not only as a congregation. A bishop with several hundred members cannot know which of them has lost a job or is caring for a dying parent; the ministering network is the mechanism by which he finds out, and it is why a Latter-day Saint family that suffers a bereavement will typically have meals arriving within hours from people who were not asked.