I have used Vimeo a number of times and once the video is uploaded you can share your video by sharing the link with others. If you video has a password, you must share the password with the people you want to share the video with. In other words, only people with the password will be able to watch your video. You can also change you password at any time if you needed to do that.
Here is a short video that shows how to password protect your video once it has been uploaded to Vimeo.