Click to Call adds a sidebar to Google Sheets that lets you quickly search rows, view row details, and trigger a call from phone-like values.
tel:https://pbx.example.com/call?to={{NUMBER}}.tel: links using your system’s default handler.The add-on reads spreadsheet values only to search and display matches. It stores only your personal settings (call mode and optional URL template). When you trigger a call in URL mode, it sends the number to the URL you configured.
You should only configure call URLs that you trust and understand.