UTM Builder — illustrative example

INPUT
Destination: https://example.com/demo; source newsletter; medium email; campaign autumn.

RESULT
https://example.com/demo?utm_source=newsletter&utm_medium=email&utm_campaign=autumn

REVIEW
Choose a consistent naming convention before generating links. Preserve existing functional query parameters and keep campaign labels out of sensitive personal data.

This is a teaching example, not a live execution record.