To add a birthday and/or work start date to a specific user:
1. Log in to your account as an Org Admin.
2. Click the settings (gear) icon on the upper right-hand side of your Dashboard.
3. Choose "Admin Panel" from the dropdown menu and navigate to the "Users" tab.
4. Next to the desired user, click the pencil icon.
5. Here, you can add a birthday and work start date, then click "Save" to update that user.
To bulk update existing users with birthdays and work start dates, from the "Users" tab click "Invite / Update user(s)" then "Update existing users". You can then follow the steps in Can I update the users on my business plan via spreadsheet upload? to update your users with this information via spreadsheet upload.