Docs updates September (#38796)

Closes #ISSUE

Release Notes:

- N/A

---------

Co-authored-by: Katie Geer <katie@zed.dev>
Co-authored-by: Marshall Bowers <git@maxdeviant.com>
Co-authored-by: David Kleingeld <davidsk@zed.dev>

docs/src/ai/billing.md

@@ -1,29 +1,42 @@
 # Billing
 
-We use Stripe as our billing and payments provider. All Pro plans require payment via credit card.
+We use Stripe as our payments provider, and Orb for invoicing and metering. All Pro plans require payment via credit card or other supported payment method.
 For invoice-based billing, a Business plan is required. Contact [sales@zed.dev](mailto:sales@zed.dev) for more information.
 
-## Settings {#settings}
+## Billing Information {#settings}
 
-You can access billing settings at [zed.dev/account](https://zed.dev/account).
-Clicking the button under Account Settings will navigate you to Stripe’s secure portal, where you can update all billing-related settings and configuration.
+You can access billing information and settings at [zed.dev/account](https://zed.dev/account).
+Most of the page embeds information from our invoicing/metering partner, Orb (we're planning on a more native experience soon!).
 
 ## Billing Cycles {#billing-cycles}
 
-Zed is billed on a monthly basis based on the date you initially subscribe.
+Zed is billed on a monthly basis based on the date you initially subscribe. You'll receive _at least_ one invoice from Zed each month you're subscribed to Zed Pro, and more than one if you use more than $10 in incremental token spend within the month.
 
-We’ll also bill in-month for additional prompts used beyond your plan’s prompt limit, if usage exceeds $20 before month end.
-See [usage-based pricing](./plans-and-usage.md#ubp) for more.
+## Threshold Billing {#threshold-billing}
+
+Zed utilizes threshold billing to ensure timely collection of owed monies and prevent abuse. Every time your usage of Zed's hosted models crosses a $10 spend threshold, a new invoice is generated, and the threshold resets to $0.
+
+For example,
+
+- You subscribe on February 1. Your first invoice is $10.
+- You use $12 of incremental tokens in the month of February, with the first $10 spent on February 15. You'll receive an invoice for $10 on February 15
+- On March 1, you receive an invoice for $12: $10 (March Pro subscription) and $2 in leftover token spend, since your usage didn't cross the $10 threshold.
+
+## Payment Failures {#payment-failures}
+
+If payment of an invoice fails, Zed will block usage of our hosted models until the payment is complete. Email [billing-support@zed.dev](mailto:billing-support@zed.dev) for assistance.
 
 ## Invoice History {#invoice-history}
 
-You can access your invoice history by navigating to [zed.dev/account](https://zed.dev/account) and clicking "Manage" on your subscription.
+You can access your invoice history by navigating to [zed.dev/account](https://zed.dev/account) and clicking `Invoice history` within the embedded Orb portal.
 
-From Stripe’s secure portal, you can download all current and historical invoices.
+If you require historical Stripe invoices, email [billing-support@zed.dev](mailto:billing-support@zed.dev)
 
 ## Updating Billing Information {#updating-billing-info}
 
-You can update your payment method, company name, address, and tax information through the billing portal.
+Email [billing-support@zed.dev](mailto:billing-support@zed.dev) for help updating payment methods, names, addresses, and tax information.
+
+> We'll be updating our account page shortly to allow for self-service updates. Stay tuned!
 
 Please note that changes to billing information will **only** affect future invoices — **we cannot modify historical invoices**.
 
@@ -31,7 +44,7 @@ Please note that changes to billing information will **only** affect future invo
 
 Zed partners with [Sphere](https://www.getsphere.com/) to calculate indirect tax rate for invoices, based on customer location and the product being sold. Tax is listed as a separate line item on invoices, based preferentially on your billing address, followed by the card issue country known to Stripe.
 
-If you have a VAT/GST ID, you can add it at [zed.dev/account](https://zed.dev/account) by clicking "Manage" on your subscription. Check the box that denotes you as a business.
+If you have a VAT/GST ID, you can add it at during checkout. Check the box that denotes you as a business.
 
 Please note that changes to VAT/GST IDs and address will **only** affect future invoices — **we cannot modify historical invoices**.
 Questions or issues can be directed to [billing-support@zed.dev](mailto:billing-support@zed.dev).