Select the individual within the household and find the "Take Survey" button in their profile. You can also access it via the Action menu by tapping the grid icon in the top right corner.

You’ll be presented with a list of surveys in your nation (if they are set to Published or Unlisted). Tap a survey to begin.

 
Multiple choice and Yes/No questions will appear as shown below. Select the response and tap “Next”.

 
Once the survey is finished, be sure to tap Submit Answers to sync the responses back to your nation.

If you have Admin access to your nation, check that your survey’s are attached to a Survey page and the status of the page is Published or Unlisted.

For more info, follow our guide to setting up surveys.