You may trigger the cycle kick-off notification for the employees whom you are adding to the cycle.
To send a cycle kick off notification while confirming the employees
1. Navigate to Admin > Most Popular Configurations > Process Cycles (Goals/Reviews)

2. Click the Edit icon next to the cycle name in which the employee is to be added.

3. In the second step, add the employees to the cycle using the Bulk Add Participants or Add Participants option.

4. Once you add the employees, click the "Save & Continue" option to proceed with the next steps.
5. In the third step, you can view the employee count you added to the cycle in the To be Confirmed tab.
6. Enable the Send process kick-off email notification to confirmed employees button first and click on the Save & Confirm to send the kick-off email only for the employees in the "TO BE CONFIRMED" state.

After initiating the cycle and confirming the employees, if you need to add any additional employees later, simply add them to the respective cycle, then enable the “Send process kick-off email notification to confirmed employees” option and click Save & Confirm. The email notification will be sent only to the newly added employees.
If the employees are already confirmed in the cycle and you wish to send the kick-off email notification only to a specific employee, remove the employee from the cycle and add them again. Then, follow the same steps mentioned above to trigger the kick-off email.
OR
You may follow the steps defined in the given article - How to send Kick off/welcome email to employees already added/confirmed in the cycle
PS: Synergita implementation for your Organization may vary from how the features are described here. The screenshots given here may also be different from what you see in your system. Please talk to the concerned person in the Organization for any specific queries.
