Discuss about the security levels which are assigned to users ?

Answer:

The administrator will assign the Security levels who is adding the user. There are four levels by default which are discussed as follows:

1) Reader - In this level, the user will have read-only access to the Web site.
2) Contributor - The user can add content to existing document libraries and lists.
3) Web Designer - The user can create lists and document libraries and customize pages in the Web site.
4) Administrator - The user will have the full control of the Web site.