How to add a customer to the ticket via APIs?

Hi,

I was looking into the ticket creation API and the request body accepts only,
{
“subject”: “Subject”,
“issue”: “Issue Exmaple”,
“owner”: {OwnerId},
“group”: {GroupId},
“type”: {TypeId},
// Note: Priority must be priority id associated with the selected type id
“priority”: {PriorityId}
},

How do I add the customer to the ticket?