If you are going to submit business verification for Facebook APP review process, Before submiting follow this best practice to get approval .
1. Website Address: You need to give website of your business. It not necessary to give the FB Inboxer website for business verification. You need to give the website of your business that you are submiting the documentation. Also make sure that your website is complete . Atleast need some content , containing your business name & address .
2. Make sure you are giving the business email of your website.
As example , Use email for you : email@example.com
If you don't have that email, open email from your cpanel.
3. And for signing contract, give a name of other person as desingation like COO or Software Engineer or something. And give email like firstname.lastname@example.org
4. Also make sure the documentation you are submitting have the name of your business & address clearly.
Business verification is needed one time for your account. It will not need for every app you submit.
Business Verification Submission Process : (Example )