That's a tough question, but I think that web dev is probably the fastest path to employment.
Web dev is very all encompassing though. There are two parts to web dev and you can learn one or both. They are:
Front End - What the user sees and what occurs in the browser
Back End - What the user doesn't see and what happens on the server
If you want to become employable quick a good path may be to learn the following:
Front End:
HTML - The very basic building blocks of web dev
CSS - Works with HTML to shape the look and feel of a website
Javascript - Adds interactivity to websites and allows for doing things when a user clicks, loading content in response to a user's action, etc
Back End:
PHP - One of the easiest programming languages to learn (in my opinion), allows you to add interactivity to websites
Wordpress Theme and Plugin Development -
Wordpress powers over 40% of all the websites on the internet, so knowing it ensures there's a market for you
MySQL - A very common database language for storing user data / creating user accounts, etc.
Further Study:
Laravel Blade + Sage 9 for Wordpress - A framework for more modern development on Wordpress, which helps alleviate a lot of the issues with Wordpress development and a lot of the bad practices.
There are other paths for web dev as well, such as focusing on the Javascript route and getting a job coding in Node JS or one of the many Javascript frameworks such as Vue or React. You have to determine what you like and what your local job market is demanding.
I will say though knowing back end + front end will make you more valuable than someone who just knows one or the other. If you want to learn both, I recommend starting with front end to learn the building blocks, then back end to enhance your skills.