High level there are two ways of doing this:
1. Payment Pages 2.0 (HPM)
You can embed a custom URL on the invoice which directs to your webpage which has the HPM iframe embedded, enabling the customer to enter the payment method which then can be directed to Zuora.
Its highly recommended to:
capture the payment method upfront during the initial order and use payment run functionality to automate the collections process.
have customers not skip the log in stage for various fraud protection, security and lead generation reasons.
2. Self Service Portal
Zuora offers a self-service portal add-on (https://connect.zuora.com/appstore/apps/subscriber-self-care-portal-1) that you can invest in, to take care of the complete end-to-end signup/checkout process seamlessly for you.
Hope this helps!
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