Please find the instructions mentioned below:
Go to Edit Code > Snippets > payment-icons.liquid file

Click to make changes according to Shopify Manual
Replaced the code according to Shopify Manual

This is how it will look like.

Please find the instructions mentioned below:
Go to Edit Code > Snippets > payment-icons.liquid file
Click to make changes according to Shopify Manual
Replaced the code according to Shopify Manual
This is how it will look like.