To insert a Woonder icon into your custom text/HTML, you can use the HTML i tag:
<i class="ws ws-tag" aria-hidden="true"></i>
You can change the two colors of the icons in the theme customizer settings: Appearance » Customize » General » Global Colors. Set the Primary custom icon color and Secondary custom icon color options.
Here is the list of all icons with their classes:
            class: 
ws ws-yen
         
            class: 
ws ws-tag
         
            class: 
ws ws-return
         
            class: 
ws ws-coins-1
         
            class: 
ws ws-sign
         
            class: 
ws ws-heart
         
            class: 
ws ws-wallet
         
            class: 
ws ws-shopping-bag-2
         
            class: 
ws ws-delivery-truck-1
         
            class: 
ws ws-delivery-truck
         
            class: 
ws ws-ticket
         
            class: 
ws ws-task
         
            class: 
ws ws-chat
         
            class: 
ws ws-shopping-basket
         
            class: 
ws ws-shopping-bag-1
         
            class: 
ws ws-loupe
         
            class: 
ws ws-percentage
         
            class: 
ws ws-review
         
            class: 
ws ws-receipt
         
            class: 
ws ws-smartphone-1
         
            class: 
ws ws-smartphone
         
            class: 
ws ws-atm
         
            class: 
ws ws-email
         
            class: 
ws ws-pin
         
            class: 
ws ws-list
         
            class: 
ws ws-hanger-1
         
            class: 
ws ws-hanger
         
            class: 
ws ws-gift
         
            class: 
ws ws-gift-bag
         
            class: 
ws ws-package-2
         
            class: 
ws ws-dollar
         
            class: 
ws ws-euro
         
            class: 
ws ws-coins
         
            class: 
ws ws-cursor
         
            class: 
ws ws-online-banking
         
            class: 
ws ws-cash-1
         
            class: 
ws ws-cash
         
            class: 
ws ws-trolley
         
            class: 
ws ws-shopping-cart-2
         
            class: 
ws ws-shopping-cart-1
         
            class: 
ws ws-shopping-cart
         
            class: 
ws ws-credit-card-1
         
            class: 
ws ws-credit-card
         
            class: 
ws ws-calculator
         
            class: 
ws ws-package-1
         
            class: 
ws ws-package
         
            class: 
ws ws-medal
         
            class: 
ws ws-barcode
         
            class: 
ws ws-shopping-bag
         
            class: 
ws ws-worldwide