Final answer:
To add a custom text field on a Shopify product page, access your Shopify Admin dashboard, navigate to the 'Online Store' section, and use Liquid code to add the custom text field.
Step-by-step explanation:
To add a custom text field on a Shopify product page, you need to access your Shopify Admin dashboard and navigate to the 'Online Store' section. From there, click on 'Themes' and select 'Customize' for the theme you want to modify. In the customization panel, find the product page template and use Liquid code to add the custom text field.
Here is an example of Liquid code that you can use:
<label for="custom-field">Custom Field:</label>
<input type="text" id="custom-field" name="properties[Custom Field]">
Make sure to replace 'Custom Field' with the name you want to use for your text field.