Any time you Mark Lost and select the reason, you can also clarify why a particular reason applies.

The notes might also help explain the customer outlook, possible issues, or opportunities.

It will also help in cases when the reason is not that obvious, and you have to select ‘Other’.

You can type up plain text or paste some important information that does not include links or images.

Overall, Notes are great drivers of information and force you and your team to think more about the customer. They will be visible to any team member who views this proposal's history.

Every time you add Lost notes they save in the history, so if you mark the proposal as lost more than once you will have a historical track of what happened.

Example of adding Lost Reasons Notes: