# Sending an event
In order to send any event, user has to be already signed in (See Register a user). Then, SDK will be able to send various events related to user and his actions such as custom events and mobile view screen.
- Objective C
Each event can be named as you wish (except for predefined ones) and can contain attributes with value types:
- string -
"this is a string"
- integer -
- boolean -
- date and time
Choose event type
We've got three event types:
Predefined events is the set of events created by us, for easier access to some data (device model, os version etc.). The amount of these will grow along with SDK.
Custom events can be created by you, and contain any information you provide (quantity of product, it's price, color etc.).
Mobile view screen events is the set of events that are created when client switches between mobile application activities and it can inform you about current state of displayed activity of your client.