You can update payment methods through your Clarity account.
To set this up:
Log in to your Clarity account
Go to Payments > Settings
Find the Saved Payment Methods section
Click "Add Payment Method" and enter your details
Once you've added a payment method, you can easily make manual payments for tuition and incidental invoices at any time.
Walkthrough: http://clarity.navattic.com/m4j04fa
Viewing Past Invoices
Go to Billing > History
Filter by month or year
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