Tracking Parameters are the UTM values added to links in your emails so tools like Google Analytics can attribute website traffic to a campaign. Go to Marketing > Email > Tracking (/admin/marketingcampaigns/trackingparameters). The UTM Parameters table has columns Active, UTM Parameter (the key, e.g. utm_source), Campaign Value (a dropdown) and a delete button.

• The standard parameters are pre-created by the system; their keys are read-only for the system-created rows, and the ones marked required cannot be switched off (saving shows This field is required - utm_...).
• Choose a value from Static options (Email, Sms, Campaign, Sprwt), Dynamic options that are filled per campaign (Message Type, Campaign name, Campaign id, Campaign name (Campaign id), Campaign name (Send date), Email Subject) or select Create new to type your own value.
• Click + Add Parameter to add a custom key/value pair and Save.

Every value must be filled (Invalid VALUE! otherwise). These defaults apply to all campaigns and flow emails that have tracking switched on and aren't using campaign-specific custom parameters.