WhatsApp Business have a payment option:

• With this application, you may showcase and share your products and services within your business account.
• Make it simple for potential customers to connect with you with a short link. To enable potential consumers to message your company, share the auto-generated short link with them.
• Tools for communicating: Create critical discussions in advance using WhatsApp messaging templates. To engage with new consumers, create automatic welcoming messages. Set aside messages to inform clients when you'll be back, or create fast responses to commonly asked questions.
• Labels: Sort your client discussions into useful categories to make operations and administration easier. You can categorise your interactions by 'New customers' or 'Pending orders.'
• This digital payments programme allows you to effortlessly create Payment Links and deliver them to your customers over WhatsApp, Instagram, SMS, and other platforms. They can click on the link and pay using their preferred method, such as credit/debit cards, netbanking, or UPI.
• Go to Settings in WhatsApp. Accept and continue after tapping on Payment. Send an SMS to verify your phone number. Upon confirmation, you'll get a list of all UPI-compatible banks.

Read More: How to use WhatsApp Business with multiple users?