There are multiple ways to create line items.

With menu item id

Line items created with a menu_item_id will inherit all the properties of the menu item. You can optionally pass in line item attributes to override those of the menu items. For Example:

{
  "data": {
    "type": "line_items",
    "attributes": {
        "booking_id": 1,
        "menu_item_id": 1
    }
  }
}

With tax inclusive pricing

Line items can be created with tax inclusiving pricing when use_tax_included_price is true and tax_included_price is provided in the request. tax_included_price is only applicable if use_tax_included_price is true. For Example:

{
  "data": {
    "type": "line_items",
    "attributes": {
        "booking_id": 1,
        "name": "Pizza",
        "tax_included_price": "15.00",
        "use_tax_included_price": true
    }
  }
}

With tax ids

Line items can be created with taxes when tax_ids is provided in the request. For Example:

{
  "data": {
    "type": "line_items",
    "attributes": {
        "booking_id": 1,
        "name": "Hotdog",
        "tax_ids": [1,2,3]
    }
  }
}