See JetBrains manual or simply:
- Project Settings | PHP | Code Sniffer - define path to
vendor\bin\phpcs, try validate - Project Settings | Inspections - PHP, tick PHP Code Sniffer validation
- In the right corner of the window, pick Custom
- In the end of the line click ... button
- Select path to dir with ruleset.xml
vendor/zenify/coding-standard/src/ZenifyCodingStandard - Apply, OK
- Restart PhpStorm
- Profit!