Is it possible to send custom user properties using HTTP API?

I currently have a custom event set up to capture user log in through Auth0 using Amplitude’s HTTP API. When I inspect the event in Users and Sessions I can see that it captured standard user properties like user id, device id, country, ect. I was wondering if it’s possible for me to send any custom data with this event. This is the code I wrote:

exports.onExecutePostLogin = async (event, api) => {
  const fetch = require('node-fetch');

  const response = await fetch('https://api2.amplitude.com/2/httpapi', {
    method: 'POST',
    headers: {
        'Content-Type': 'application/json',
        'Accept': '*/*'
    },
    body: JSON.stringify({
        "api_key": event.secrets.API_KEY,
        "events": s{
            "event_type": "User log in"
        }]
    })
  })

Let’s just say for an example I wanted to capture the user email or log in time, would it be possible for me to capture this information? Currently, when I add a key value pair to the events array in the body like `email: myemail@gmail.com` this information isn’t captured.