The basic documentation to understand the principles is in the Ionic docs.
The first step is creating a key to sign the file to upload to the Play Store:
keytool -genkey -v -keystore my-release-key.keystore -alias alias_name -keyalg RSA -keysize 2048 -validity 10000
The second step is setting your app to use this certificate.
Create a build.json file to put in your main folder:
{
"android": {
"release": {
"keystore": "MYFILE.keystore",
"storePassword": "STORE-PASSWD",
"alias": "KEY-ALIAS",
"password" : "KEY-PASSWD",
"keystoreType": ""
},
"debug": {
"keystore": "debug.keystore",
"storePassword": "",
"alias": "androiddebugkey",
"password" : "",
"keystoreType": ""
}
}
}