Shopify Expert Create Multi-Step Order Form code with functions

Please bid only if u r expert in custom coding shopify and u can add functions
will share demo site link in chat how i want

I need a custom-coded, multi-step form embedded in my Shopify theme that guides shoppers smoothly through an order-processing flow. The form must:

• let customers choose the product or service they want to buy (physical items, digital downloads, or service packages)
• collect the usual personal information, shipping details, and payment information in separate, clearly labeled steps
• integrate with, or replicate the flexibility of, a “Form Builder”-style interface so I can add or modify fields later without touching code
• update the cart in real time, respect variant pricing, and pass all data straight to the Shopify checkout