In the App Studio, users can create, list, edit and revoke their user API keys in the "My Account" -> "My Profile" -> "API Keys" section.
By default, you will have no User API keys. To create a new User API key, you can click on the "Add a new key" button. Then you will be asked to set a label for the key. The platform allows one account to have multiple API keys, so it will be useful if you set a label when you create a new API key everytime. Then you just need to click on the "Generate" button. You will see a new API key is generated immediately.

All the keys you have created for the account will be listed here. To edit a key, just click on the "Edit" button of the key you want to edit.
Then you will notice that the label field of the key become editable. You can update the label of the key, then click "Update".

An API key will become invalid if you revoke it. To revoke a key, click on the "Revoke" button of the key you want to revoke. Addtional information about when the key was revoked and by who will be displayed as well.

To use the API keys, you can click on the clipboard icon beside an API key, which will copy the key value to the clipboard automatically. Then you can use this key in FHC.
If you want to access the platform REST API programmatically, you need to set a valid user API key in the "X-FH-AUTH-USER" header field of each request.