To Make a Project Private:
If you'd like to make your project private (invisible to everyone but you), you can adjust this by going to: Edit Project --> Settings --> Project Visible To --> Edit.
To Make a Project Private, but visible to a few select Behance Members (aka "Private Share"):
To accomplish this, click Edit Settings, then "Limit Visibility." This will allow you to select specific Behance members to make your project visible to. Other than these members you choose, the general public will not be able to see your project.
Note that on Behance, there is no way to make a project private, AND visible to anyone you send the link to. For more privacy options like password protected projects, consider using our portfolio service, Adobe Portfolio (myportfolio.com)