Reference for checkoutAgreement GraphQl query (#4943)

* Reference for checkoutAgreement GraphQl query

Fixes magento/graphql-ce#767

* Requested revisions

* Move output attributes to end of document

guides/v2.3/graphql/reference/checkout-aggreements.md

@@ -0,0 +1,71 @@
+---
+group: graphql
+title: checkoutAgreements query
+contributor_name: Something Digital
+contributor_link: https://www.somethingdigital.com/
+---
+
+The `checkoutAgreements` query retrieves checkout agreements. The query will always return an empty array when the
+**Enable Terms and Conditions** option is set to **No**.  (The config path is `checkout/options/enable_agreements`.)
+
+## Syntax
+
+`{checkoutAgreements {CheckoutAgreement}}`
+
+## Example usage
+
+The following query returns enabled checkout agreements.
+
+**Request** 
+
+```text
+{
+  checkoutAgreements {
+    agreement_id
+    checkbox_text
+    content
+    content_height
+    is_html
+    mode
+    name
+  }
+}
+```
+
+**Response**
+
+```json
+{
+  "data": {
+    "checkoutAgreements": [
+      {
+        "agreement_id": 1,
+        "checkbox_text": "I agree to the terms of sale",
+        "content": "<p><strong>Agreement Contents</strong></p>\r\n<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>",
+        "content_height": "22px",
+        "is_html": true,
+        "mode": "AUTO",
+        "name": "My Agreement"
+      }
+    ]
+  }
+}
+```
+
+## Output attributes
+
+The `CheckoutAgreements` object contains an array of [`CheckoutAgreement`](#checkoutAgreementAttributes) objects.
+
+### CheckoutAgreement attributes {#checkoutAgreementAttributes}
+
+The `CheckoutAgreement` object provides the following attributes:
+
+Attribute | Data type | Description
+--- | --- | ---
+`agreement_id` | Integer! | Checkout Agreement identifier
+`checkbox_text` | String! | Label of the Checkout Agreement checkbox
+`content` | String! | The content of the Checkout Agreement. The value can be in  plain text or in HTML
+`content_height` | String | CSS height of Checkout Agreement
+`is_html` | Boolean! | Is Checkout Agreement content in HTML format
+`mode` | String! | Indicates whether terms and conditions are applied manually (`MANUAL`) or automatically (`AUTO`)
+`name` | String! | Checkout Agreement name