> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hfrapp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Pre-fill (Email, Wallet, etc.)

> Need to pass in parameters to prefill email or wallet address? We support that!

Use the optional `walletAddress` to pre-fill the wallet address

Use the optional `email` to pre-fill the email

```javascript Example
<WinterCheckout
  // Your projectId, will be the same in sandbox/production
  projectId={20}
  // When false we use tesntet & when true we use mainnet
  production={false}
  // This is a boolean that opens the widget when true
  showModal={showWinter}
  // Can pass in the customer's wallet address if you have it
  walletAddress="0x64EE4e11E0992D18C5986bA99F2d7DF8fc7A3dC3"
  // Can pass in the customer's email if you have it
  email="laila@usewinter.com"
  // Can pass in the mint quantity if the quantity is chosen before our modal is opened
  mintQuantity={5}
/>
```

If you've embedded the iframe directly, check out
[this example](https://checkout.usewinter.com/?projectId=1\&walletAddress=0xabcdefg\&email=sean@awesome.com).