Added API URL to the README

README.md

@@ -31,6 +31,14 @@ $ npm run test
 
 ## Configuration and setup
 
+### Tatum API URL
+
+Provide URL to the Tatum API to process.env.TATUM_API variable. Default URL is *https://api-eu1.tatum.io* You can use dotenv or any other way. There are modules and
+functions, that do not have to communicate with Tatum API, like wallet generation or signing of transactions locally. In
+those cases, there is no need to provide TATUM_API parameter.
+
+```process.env.TATUM_API=${YOUR_API_URL}```
+
 ### Tatum API KEY
 
 Provide Tatum API key to process.env.TATUM_API_KEY variable. You can use dotenv or any other way. There are modules and