How can an 18 year old foster child move in with a friends?

An 18-year-old foster child can typically choose to move in with a friend if they are legally an adult and have the capacity to make their own decisions. They should inform their caseworker or social worker about their decision, as there may be paperwork or procedures that need to be followed to officially change their placement. It's important to ensure that the new living arrangement is safe and suitable for the individual.