YITH WooCommerce One-Click Checkout allows users to skip the checkout process once the billing info has been added.
The integration between these two plugins allows users to enable the one-click checkout features from their My Account page.
By activating both plugins, a new endpoint will be automatically added to the Endpoints section.

You can configure the endpoint through the available options.

From the One-click checkout section, they will be able to activate the one-click checkout for their purchases and add new shipping addresses.
For further details about YITH WooCommerce One-click Checkout settings, please refer to the official documentation.