1. Add a Payment field from the Advanced Fields to your form.
   
2. In the pop-up, select the Payment Gateway from the following list to receive payments: 
   • PayPal Standard
     
   • PayPal Checkout
     
   • Stripe
     
   • Stripe Checkout
   • 2Checkout
     
   • Razorpay
     
   • Authorize.Net
     
   • Paytm
     
   • Instamojo
     
   • PayTabs
     
   • Square
     
   
   
   
   
3. In the Payment Settings pop-up, enter a label for the Payment field.
   
   
   
   
   
4. To make the Payment field mandatory, select Mandatory.
   
5. Select the Payment Type to either be Fixed Amount or Modifiable Amount:
   
   Fixed Amount
   If you are looking to collect a fixed amount that cannot be modified by your respondents, choose Fixed Amount as the payment type. For example, if you want to collect a registration fee for your workshop/event, you can choose this payment type to collect a fixed fee that cannot be modified in the live form. You can either enter the fixed amount or auto-fill the amount from a form field.
   
   

   
   
   
   Modifiable Amount
   

   If you are looking to collect payments that are not fixed, choose Modifiable Amount to allow your respondents to modify the payment amount. For example, if you wish to collect donations, you can choose this payment type to let your respondents donate an amount of their choice by modifying any specified amount. You can either enter the modifiable amount or autofill the amount from a form field. 
   

   
   
   If you choose to enter an amount range, 
   1. Enter a minimum amount that your respondents must pay under Min. Amount. This is mandatory to ensure that the amount cannot be modified to 0 by the respondents. 
      
   2. If you wish to set a limit on the maximum amount that your respondents can pay, enter the Max. Amount. Setting a maximum limit for the payment amount will prevent any unintentional large payments.
      
   3. You can also enter a Default Amount that will be displayed to the respondents when the form loads initially, as well as when you switch merchants in the live form. By specifying a default amount, you may probably receive payments as specified. Respondents can, however, overwrite the default amount displayed and enter an amount of their choice within the set minimum and maximum range.
      

   If you choose to autofill the modifiable amount from a form field, 
   

   1. Select a form field from the drop-down. The field responses will be used to autofill the payment amount. The respondents can overwrite the auto-filled amount in the live form and enter a value of their choice.
      
   2. If you wish to set a limit on the minimum and maximum amount that the respondents can pay, select Set Range and enter the minimum and maximum values. Setting a range for the payment amount will ensure that you do not receive payments that are too low or too high.
      
   3. You can also enter a Default Amount that will be displayed to your respondents if the chosen form field to autofill the amount is empty when the form loads initially or when you switch merchants.
      
   4. You can use the Autofill from Form Fields option when you want to use the field responses to pre-fill the payment amount. For example, in an order form, you can charge your customer based on the product they choose from a dropdown list.
      
      Supported Field Types to Autofill Payment fields
      
      Number, Decimal, Currency, Slider, and Rating can be used to autofill the Payment Amount. You can also use Radio, Checkbox, Multiple Choice, Dropdown, and Image Choice fields if you have assigned values to these fields. 

6. You can configure multiple payment gateways to let your respondents choose from and make payment as shown by clicking + Add Merchant. This lets your respondents pay using a provider they already use, or are at least familiar with. This way, you can cut down any drop-off at the checkout!
   
   
   You can also rearrange the payment gateways by clicking the Rearrange link.
   
   

   

   
   

    

7. Workflow

Under Workflow, you can choose to trigger the following actions only on successful payment with Payment Status as Completed, or COMPLETED :

1. Approval processes
   
2. Email, SMS, and Push notifications
3. Rules configured for assigning tasks and sending emails
   
4. Integrations 

For example, if you have a subscription form, and you have configured to trigger an email notification to your subscribers, selecting the Workflow option will send emails only if their payment has been successful.
Similarly, order confirmation emails from your order form, or sending customer/transaction information to your CRM (if you've integrated your CRM with Zoho Forms), will only happen on successful payment transaction.

Note: The above actions will not be triggered if the Payment Status is Processing, Failed, Processing not needed, CREATED, or Card Declined.