Add brief page on NTTs

docs/concepts/tokens/nfts/non-transferable-tokens.md

@@ -0,0 +1,15 @@
+---
+seo:
+    description: Create NFTs that can't be traded among users.
+labels:
+  - Non-fungible Tokens, NFTs
+---
+# Non-Transferable Tokens
+
+The XRP Ledger supports non-transferable tokens (NTTs), sometimes called soulbound tokens, as a specific class of [non-fungible tokens](./index.md). Non-transferable tokens may be used for certifications and identity tokens, achievements in games, or other cases where the purpose of the token is limited to one person specifically.
+
+Any NFT in the XRP Ledger that has the **Transferable** flag disabled is a non-transferable token. This flag is set when the NFT is minted using the `tfTransferable` flag of the [NFTokenMint transaction][]. After the NFT is created, the transferable status is recorded as the `lsfTransferable` flag of the [NFToken object](/docs/references/protocol/data-types/nftoken/).
+
+Non-transferable tokens can still be transferred _to_ or _from_ the issuer of the token directly, but users cannot transfer the token among themselves.
+
+{% raw-partial file="/docs/_snippets/common-links.md" /%}

sidebars.yaml

@@ -128,6 +128,7 @@
                 - page: docs/concepts/tokens/nfts/collections.md
                 - page: docs/concepts/tokens/nfts/guaranteeing-a-fixed-supply.md
                 - page: docs/concepts/tokens/nfts/nft-apis.md
+                - page: docs/concepts/tokens/nfts/non-transferable-tokens.md
             - page: docs/concepts/tokens/transfer-fees.md
             - page: docs/concepts/tokens/decentralized-exchange/index.md
               expanded: false