I think the only admin tool that will allow you to accomplish this is a product called Lightning Flow, and there are a few Trailheads that can help you get your feet wet with this product.
However, you may want to shy away from what you are asking about or at least think it through a little more. The reason I say this is because: to ensure you get the correct Account it would require that every account name in SFDC to be unique, and it would also require that the customer submitting the Web-to-Case to enter in the name of their account exactly as it appears in SFDC.
I don't think you can confidentially make sure you have found the correct account without those two things being true.
Some last warnings about Lightning Flow is that it's resource heavy, it may not be coding, but it is development so you should create your flow in a sandbox before implementing in Production, and lastly Lighting Flow does NOT have error handling or in other words, errors can be confusing and hard to diagnose for admin and user.