How to show additional custom details field under the customer for placing the order from online store on Mobile?

To add additional contact information for the customer during the payment process in Online store refer the below mentioned article:

Step 1: Know Click on More and go to Online Store >> Click on View Store.

Step 2: Select any Product from the Store >> go to Cart >> Click on Proceed to Checkout.

Step 3: PAN is added as New field in the Contact Information.