I checked wkhtmltopdf, it is used as a lambda layer.
If you just want to use it without modification. You don't need to download it, just add the layer in your lambda.
- Open the Functions page of the Lambda console.
- Choose the function.
- Scroll down to the Layers section, and then choose Add a layer.
- Input Specify an ARN
- Choose Add.
https://docs.aws.amazon.com/lambda/latest/dg/adding-layers.html