The preferred way to install this extension is through composer.
Either run
composer require --prefer-dist codexten/yii-mailjet:"^2.0.0"
or add
"codexten/yii-mailjet": "^2.0.0"to the require section of your composer.json.
return [
// default mailer
'mailer' => 'mailjet',
//mailjet
'mailjet.apikey' => '',
'mailjet.secret' => '',
];