From the User Listing page:
1. Find the user, click on the Actions button, and select Edit.
2. Check set random password to auto-generate a password or insert a password in both fields.
3. Check “Should change password on next login” and “Send Activation Email”. Click on Save.
5. The user will receive the login details.
Immediately after login, the user will be presented with a Change Password screen. After inserting a new password, the user will be logged in to the account automatically.