The Salesforce integration tab is found within the main Integrations tab on each of your Sites:
To begin exporting data to Salesforce, check the “Enable Continuous Salesforce Exporting” checkbox and then click the “Save Salesforce Settings” button. The first time you enable the integration, you will need to follow the prompts to grant us access to your Salesforce data.
A Customer in Chargify becomes an Account (with associated Contact) in Salesforce.
A Subscription in Chargify becomes a Note attached to the customer’s Account in Salesforce.
We will sync data to Salesforce when a new Subscription is created, when an existing Customer is updated, or when an existing Subscription is updated such as for a renewal, product change, or payment.
Note that if a Customer without a Subscription is created in Chargify, nothing will be synced to Salesforce.
Older activity is not synced to Salesforce. Only new signups that happen after you enable the integration will be sent to Salesforce.
This Salesforce knowledgebase article on Managing OAuth Access for Your Connected Apps states that “The default limit is five access tokens for each application.”