You may need a business or corporate tax number for "Machine Learning Mastery", the company, for your own tax purposes. This is common in EU companies for example.
The Machine Learning Mastery company is operated out of Puerto Rico.
As such, the company does not have a VAT identification number for the EU or similar for your country or regional area.
The company does have a Company Number. The details are as follows:
Company Name: Zeus LLC
Company Number: 421867-1511