In this step-by-step guide, we’ll walk you through how to add a tip at the WooCommerce checkout with the help of a WordPress plugin.
Collecting tips in your online store – Ecwid Help Center
php - Add fees based on custom selected options in WooCommerce Cart page - Stack Overflow
How to Edit & Customize Your WooCommerce Checkout Page
How to Add WooCommerce Tip at Checkout
Order Tip for WooCommerce – WordPress plugin
WooCommerce Checkout Optimization - 23 Conversion Tips
How to Create and Customize WooCommerce Checkout Page Template
How to Add a Tip at WooCommerce Checkout? - AovUp (formerly Woosuite)
How to Add Checkout Tipping - Orderable