I want to add a single word invocation name for Alexa, in documentation its mentioned that a single word is allowed.
One-word invocation names are not allowed, unless: The invocation name is unique to your brand/intellectual property with proof of ownership established through legitimate documentation, or (German skills only) The invocation name is a compound of two or more words. In this case, the word must form an actual word in the skill's language to ensure that Alexa can recognize it.
But I can't find anything on alexa console.
For development, you can use the single word invocation on Alexa console and it should work. The rules for invocation names will be applicable during the publishing process. So if you want to use a single word invocation, you need to prove that you own the brand related to that word.