Each manager can choose their preferred method for keeping notes of highlights, decisions, actions that come out of a quality conversation. A spreadsheet or a table will work, or sharing an email that briefly summarizes. Not all conversations will require it, so managers will use their own discretion. It could also be helpful to have the employee summarize in an email.
Documentation is required when a performance challenge has been identified. If it is a serious incident or an ongoing issue that needs to be addressed, two things are important to attend to: 1) contact your HR Consultant to get input on what action and documentation is required; and 2) the incident or issue is written down with sufficient detail, accompanied by details of the agreed upon action to be taken.