If you are using the following version of VSCode as you can see Help -> About,
Version: 1.60.2 (user setup)
Commit: 7f6ab5485bbc008386c4386d08766667e155244e
Date: 2021-09-22T12:00:31.514Z
Electron: 13.1.8
Chrome: 91.0.4472.164
Node.js: 14.16.0
V8: 9.1.269.39-electron.0
OS: Windows_NT x64 10.0.18363
Simply go to the Run menu and click on Open Configurations, the image is given below.

This will open launch.json
, now you can add env details specific to your environment details. The example is given below.
{
"configurations": [
{
"type": "java",
"name": "Spring-Boot-App",
"request": "launch",
"cwd": "${workspaceFolder}",
"console": "internalConsole",
"mainClass": "com.blr.appName.ApplicationName",
"projectName": "projectName",
"args": "",
"env": {
"PROJECT_NAME": "FOO_PROJECT",
"licenseKeyDetails":"license_details",
"serialNumber":"ABCDEFG"
}
}
]
}