How do I add a link to my lead/contact's Salesforce detail page when sending an alert from Marketo?
If the lead or contact is in both Marketo and Salesforce at the time when the alert email is sent, then the link to the Salesforce detail page will be automatically appended to the alert email sent by Marketo.
You will need to use the "Send Alert Info" token within your Alert email while designing your email in the Design Studio of Marketo.
Below is what the generated alert looks like once it is sent from Marketo (note the link to the Salesforce detail page is automatically inserted):
Note if the lead or contact is not in Salesforce then there is no link to the Salesforce detail page: