By default, you can send GET, POST, PUT, or DELETE HTTP requests to a component. With the property httpRequestMethods you can define, which HTTP methods are allowed. Additionally, you can add support for the OPTIONS method:
{
"name": "appmixer.utils.http.WebhookWithOPTIONS",
"description": "Support for OPTIONS and POST",
"webhook": true,
"httpRequestMethods": [ "POST", "OPTIONS" ],
...
}