How do you make a pulldown field populate the speadsheet to form field?

How do you make a pulldown field populate the speadsheet to form field? I saw one thread on the update/calculate field but cannnot find this function.

Thank you.

Please kindly refer to this guide for details about how to set up the conditions to achieve it: https://www.jotform.com/help/268-How-to-Insert-Text-or-Calculation-into-a-Field-Using-Conditional-Logic

If you have questions, let us know.