Thanks for taking the time to ask your question here in the community. I'd be happy to help you with this.
Setting up a file number in the place of a company name is completely up to you. Just so you're aware, this number will be used for verification purposes with our support team, rather than your company name.
If you'd like to change the company name to a number instead, just click Company > Company Information. Here, you're able to edit the current name of the company.
I hope this helps answer your question. If you have any other questions, please don't hesitate to ask me in the comments section below.