Use a search input:

• when you want give users the possibility of finding information that is not immediately visible
• when there could be multiple results from different sources

Don't use a search input:

• when there are limited options a user can pick from (use a dropdown instead)
• if you want users to filter results from a predefined set of options

• If you have limited vertical space, use the placeholder instead of the label (but try and use the label wherever possible as it is clearer and more accessible).
• Use the size of the input to suggest how many characters a user should enter — so if you only need a few characters, don’t make it too wide.

• Only use the information message if you have evidence that users need more context.