Any text within the Ecommerce store can be customized to update it from the default store text. While this cannot be done directly in the Architect UI, you may use the handy Ecwid Translate Tool (Architect’s Ecommerce system is powered by Ecwid):
https://www.ecwid.com/playground/translate-tool/index.php
The Translate Tool allows customization of any text, button, navigation, etc. This method requires placing a bit of code in the header HTML, but it’s very easy. In the example below, we will change the “Add to Bag” buttons to show “Add to Cart”.

Navigate to the Translate Tool. Find the text you wish to change. Since the list is so long, using your browser’s “Find” tool is handy. Ctrl/Cmd + F brings this function up on most browsers. Enter the text you wish to customize. In this example, we’ll change “Add to Bag” to “Add to Cart”.

In the text field on the right, enter the new text. Click “Generate”. Note that you may enter as many instances of customized text as you like. Clicking Generate anywhere on the page will add all customized text instances to the generated code. Copy the short bit of code that is generated:

Back in Architect, navigate to Settings > Header HTML. Paste the code and click save.
Your “Add to Bag” buttons will now show “Add to Cart”:

As mentioned above, the generated code may contain as many instances of customized text as you wish. This process may be done a single time to update all of your customizations at once, instead of repeating the process each time.