Update README.md

added the Overview section - please review content and edit if I have misstated anything

Signed-off-by: Diane Mueller <[email protected]>

Author: dmueller2001

README.md

@@ -16,6 +16,21 @@ This library is using [Hiero Python SDK](https://github.com/hiero-ledger/hiero-s
 2. [Getting started](#getting-started)
 3. [Configuration](#configuration)
 4. [Contributing](CONTRIBUTING.md)
+   
+## Overview
+
+Identity networks are set of artifacts on Hedera Consensus Service that allow applications to share common channels to publish and resolve DID documents, issue verifiable credentials and control their validity status. These artifacts include:
+* address book - a file on Hedera File Service that provides information about HCS topics and appnet servers,
+* DID topic - an HCS topic intended for publishing DID documents,
+* and VC topic - an HCS topic playing a role of verifiable credentials registry.
+   
+This SDK is designed to simplify :
+* creation of identity networks within appnets, that is: creation and initialization of the artifacts mentioned above,
+* generation of decentralized identifiers for Hedera DID Method and creation of their basic DID documents,
+* creation (publishing), update, deletion and resolution of DID documents in appnet identity networks,
+* issuance, revocation and status verification of Verifiable Credentials.
+   
+The SDK does not impose any particular way of how the DID or verifiable credential documents are constructed.
 
 ## Documentation