When importing users, you have the option to send an onboarding email to imported users. This can be accomplished by checking the box marked "Send onboarding email to imported users" when uploading users via .CSV or adding them individually by email.
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When this option is checked, all new users who receive a license will receive an onboarding email.

Important Note: Only users who are assigned a license will receive an email. If you have the LICENSE field set to FALSE in your CSV, the user will not receive a license or onboarding email.
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The onboarding email learners receive is shown below (as long as SSO is not enabled):
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If your organization is using SSO, they will receive the following email:
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