Delta Reporter Reporter
wdio-delta-reporter-service is a 3rd party package, for more information please see GitHub | npm
A WebdriverIO reporter plugin to create Delta reports

Installation
The easiest way is to keep @delta-reporter/wdio-delta-reporter-service as a devDependency in your package.json.
{
"devDependencies": {
"@delta-reporter/wdio-delta-reporter-service": "^1.1.9",
}
}
You can simple do it by:
npm i @delta-reporter/wdio-delta-reporter-service