There are several platforms that help you manage your A/B tests. They often provide you a WYSIWYG editor for changing your page variations. They also often let you adjust the weights of the variations: whether you want to split the test 50-50, or 80-20, or 90-10, etc.
We work great with most A/B testing platforms. Generally speaking, you will set up the rules of the test through the platform and include a small piece of code to record which variation was viewed (the third component to every A/B test).
Updated about 2 years ago