You can share a YouTube account easily with others by setting up a Brand Account and adding different users as members. Those users will then be able to contribute to the brand page's account by switching accounts. (This also works with Google Photos.)
YouTube Partner Program
In order to add annotations to your video, you'll need to be part of the YouTube Partner Program, which also lets you monetize your videos. There are high standards for viewership for eligibility; check YouTube's informational page for the latest.