Including information about Premium Support billing (#52904)

Co-authored-by: Ben Ahmady <32935794+subatoi@users.noreply.github.com>

content/support/learning-about-github-support/about-github-premium-support.md

@@ -68,6 +68,24 @@ Incident management | None | For urgent priority tickets, as needed
 
   {% endnote %}
 
+## Billing for {% data variables.contact.premium_support %}
+
+How you are charged for {% data variables.contact.premium_support %} will depend on your {% data variables.product.github %} products and how you are charged for them.
+
+* If you are a **licensed billing** customer, the support fee percentage is applied to the cost of licenses for the current year.
+
+* If you are a **metered billing** customer, the support fee percentage for **{% data variables.product.premium_support_plan %}**, **Premium Plus plan**, and **{% data variables.product.microsoft_premium_plus_support_plan %}** is calculated as either a percentage of your estimated metered spending or a set minimum annual fee—whichever amount is higher. For {% data variables.product.microsoft_premium_plus_support_plan %} customers, this is in addition to the Unified Support contract fee.
+
+  The support fee for metered billing is estimated from the previous 12 months' spending. If you have less than 12 months of spending history, {% data variables.product.github %} will take a 12-month run rate based on your spending history. If your last 3 to 6 months spending is vastly different to the last 6 to 9 months, the last 3 to 6 month period will be used.
+
+  If you are switching from **licensed billing to metered billing**, your support fee at contract renewal is estimated based on the previous year's purchased licenses. Minimum thresholds remain in place.
+
+* If you are both a licensed and metered billing customer (hybrid), your charge will be calculated from the support fee percentage applied to the current year's license purchases **plus** the support fee percentage applied to your estimated metered billing spend.
+
+New {% data variables.product.github %} customers who are only planning to use metered products will be required to pay the annual minimum for {% data variables.product.premium_support_plan %} or {% data variables.product.premium_plus_support_plan %}.
+
+If you would like a quote for {% data variables.contact.premium_support %}, contact [{% data variables.product.github %}'s Sales team](https://github.com/enterprise/contact?scid=&utm_campaign=2023q3-site-ww-PremiumSupport&utm_content=Premium+Support&utm_medium=referral&utm_source=github).
+
 ## Signing up for {% data variables.contact.premium_support %}
 
 To sign up for {% data variables.contact.premium_support %} or upgrade your plan, [contact our account management team](https://enterprise.github.com/contact).