Does limesurvey has user access feature, that a user must login the system to do the survey or assessment? Is it possible to view the sample survey or assessment result, such as percentage of respondents to different answers by the user or anyone?

Hi,
In most cases survey access is restricted using tokens. A respondent can only do the survey with a valid token. As a user with admin permissions, you will be able to preview your survey when it is not yet activated, or access it from the token table using a valid token when it is.
The admin menu also offers some statisitic options which I am not familiar with.
Assessments as implemented in LimeSurvey are volatile and will only be visible to the respondent when doing a survey.
Hope this helps!
Frank

Hi, Rebecca,
to add something:
You can set a survey to "open", meaning that anybody who has the link is able to answer the survey, e.g. a link provided on a web page or so.

Also there are survey options to let the respondent see public statistics - with or without charts - after submitting the questionnaire.

Kind regards
Joffm