How do I make closed won/lost reason mandatory when closing a deal?

I have been trying to find a solution to this but cannot find any mandatory checkboxes in the manage properties section. Help would be appreciated.

Thanks

Hi @LillKleven,

Under Settings > Objects > Deals > Pipelines, hover your mouse over the Closed lost stage, then click Edit properties. You can now set a checkbox.

This is also explained here: Set up and manage object pipelines

Best regards!