You have to request your vendor to provide you a valid tax invoice with all mandatory contents as prescribed by UAE VAT Law. In absence of the tax invoice, you would not be able to recover the VAT charged by vendor as input tax and it will result in a additional cost to you. I have assumed that you are asking on behalf of a VAT registered entity.

UAE VAT law does not prescribe any leniency in this regard. So one should only avail input VAT based on valid tax invoice which all specific particulars as prescribed in Article 59 of UAE VAT law.