WebHooks - marcocusano/discord-php GitHub Wiki
channel 
Returns a list of channel webhook objects. Requires the MANAGE_WEBHOOKS permission.
$discord->webhooks->channel("CHANNEL_ID");
create 
Create a new webhook. Requires the MANAGE_WEBHOOKS permission. Returns a webhook object on success.
$scope = "channel"; // or "guild"
$params = array( "name" => "WebHookName" );
$discord->webhooks->create($scope, $params);
delete 
Delete a webhook permanently. User must be owner. Returns a 204 NO CONTENT response on success.
$discord->webhooks->delete("WEBHOOK_ID");
edit 
Modify a webhook. Requires the MANAGE_WEBHOOKS permission. Returns the updated webhook object on success.
$params = array( "name" => "NewWebHookName" );
$discord->webhooks->edit("WEBHOOK_ID", $params);
execute (alpha) 
This endpoint supports both JSON and form data bodies. It does require multipart/form-data requests instead of the normal JSON request type when uploading files. Make sure you set your Content-Type to multipart/form-data if you're doing that. Note that in that case, the embeds field cannot be used, but you can pass an url-encoded JSON body as a form value for payload_json.
$discord->webhooks->execute("WEBHOOK_ID", "WEBHOOK_TOKEN");
get 
Returns the new webhook object for the given id.
$discord->webhooks->get("WEBHOOK_ID");
guild 
Returns a list of guild webhook objects. Requires the MANAGE_WEBHOOKS permission.
$discord->webhooks->guild("GUILD_ID");