Environment variables are stored safely in our database, so you can focus more on developing code instead of taking care of security.
To create a new environment variable, go to the app in the main bar (on top).
Click on Easy for Jira
On the left side, click on the configuration Cog 
Here you can manage your variables.
Once you create, you can’t edit it, so if you want to use the same key, delete your existing one and recreate. This is designed like this for security measures.
Once you create your variables, you can see them in the table below as follows:
Using my environment variables on my code
On your code, you can call the variables as follows
openai.api_key = env["OPENAI_API_KEY"]
This also works for the Code Repository
You can / should reference your keys on the repository.
Future State
We are working to have an extra layer of security by checking your code before saving it and automatically creating an environment variable for that, that will be available in next patches.
Also, the UI in the configurations section will be revamped.