Brian Henry

Add <code>?payment_gateway=preferred_gateway_id</code> to links in emails you send to your customers, and when they reach the 
checkout, that will be the selected payment gateway.
A WordPress filter exists so the text in the URL can be set to whatever you prefer.
<a href="https://github.com/brianhenryie/bh-wc-set-gateway-by-url/" rel="nofollow ugc">Technical detail is on GitHub</a>.

Set WooCommerce Payment Gateway by URL

Set the WooCommerce payment gateway in URLs sent to customers.

clint.s

Love WordPress? Love Bitly? After installing this plugin, you’ll be able to shorten a link and view clicks right from WordPress. Your new links will be saved to Bitly for reference and deeper analysis.
To do that, you must have a Bitly account to use the plugin. Your account is where you store, edit, and view metrics for your links. Register at bitly.com.
No matter the type of site you own (from a personal blog to an ecommerce store and everything in between) Bitly makes it easy to create shorter links and keep an eye on your clicks. Whether you share your links on social, SMS, or email, a short link is easier to manage and remember.

Bitly's WordPress Plugin

Simple & awesome Plugin :-) 
Easy to Configure it with Bitly.


Much Needed Plugin

Create short links to your content with Bitly’s WordPress Plugin.

Set WooCommerce Payment Gateway by URL vs Bitly's WordPress Plugin