When users ask this question to government, the answer now is...it depends.
Our team's hypothesis is these patterns and guidance can change that:
Help users find and understand your service.
Published guidance:
Help users understand whether they can and should use a service.
Example:
Prototypes:
Show users all the tasks involved to do something.
Example:
Prototypes:
Prototypes for each round of research with users.
Prototypes: