you can need to change the password in config file " config.json "
"api": {
"enabled": true,
"hashrateWindow": 600,
"updateInterval": 5,
"port": 8117,
"blocks": 30,
"payments": 30,
"password": "your_password"
},
"password": "your_password"here in config file you need to change the password as er your need ..or you can use the default one " your_password " not recommended