Ivan Popov

This plugin lets you attach an extra fee — either a percentage of the cart subtotal or a fixed amount — to any WooCommerce payment gateway or shipping method. Configuration lives under WooCommerce → Settings → Checkout Fee.
Typical use cases:
<ul>
<li>Pass card-processing surcharges to customers paying with specific gateways.</li>
<li>Add a handling fee for Cash on Delivery.</li>
<li>Add a packaging/insurance fee for express shipping methods.</li>
</ul>
Features:
<ul>
<li>Per-method configuration — every payment gateway and shipping method has its own settings.</li>
<li>Choose between a percentage of cart subtotal or a fixed amount.</li>
<li>Optional taxable flag so the fee can be included in tax calculations when required.</li>
<li>Customisable fee label shown to the customer.</li>
<li>Works with the classic checkout and the block-based Cart & Checkout.</li>
<li>Declares compatibility with WooCommerce High-Performance Order Storage (HPOS).</li>
</ul>

Payment and Shipping Method Checkout Fee for WooCommerce

Add a percentage or fixed fee to any WooCommerce payment method and shipping method at checkout.

ByteJutsu

ByteJutsu Fixed Order Fee For WooCommerce lets you add a fixed fee to WooCommerce orders, with an adjustable amount and label from the WooCommerce settings.
This plugin provides: 
* A fixed fee configurable from the WooCommerce settings page. 
* Options to set the fee amount and the fee label. 
* The fee appears in the cart, checkout, and order totals. 
* Automatically applies the fee for customers during checkout, and for admins when creating or editing orders.
Key Features: 
* Adjustable fixed fee for all orders. 
* Customizable fee label. 
* Lightweight implementation that does not modify WooCommerce core files.
<h4>How to Use</h4>
<ol>
<li>Install and activate the plugin.</li>
<li>Make sure WooCommerce taxes are enabled (otherwise the Tax tab is hidden).</li>
<li>Go to WooCommerce > Settings > Tax > Fixed order fee.</li>
<li>Set the fixed fee amount and label, then save changes.</li>
<li>The fee will be applied to new WooCommerce orders.</li>
</ol>
<h4>Requirements</h4>
<ul>
<li>WordPress 5.0 or higher.</li>
<li>WooCommerce 4.0 or higher.</li>
<li>PHP 7.0 or higher.</li>
</ul>
<h3>License</h3>
This plugin is distributed under the GPLv2 or later. 
See the included license.txt file for full license text.
<h3>Support</h3>
For inquiries, feature requests, or support, please contact: contact@bytejutsu.dev

ByteJutsu Fixed Order Fee for WooCommerce

This plugin adds a customizable fixed fee to WooCommerce orders with an easy-to-configure amount and label.

Payment and Shipping Method Checkout Fee for WooCommerce vs ByteJutsu Fixed Order Fee for WooCommerce