The conditions in plain English
The Ministry of Finance lists exports of goods and services to destinations outside the GCC among zero-rated supplies. The detailed conditions for services are in Article 31 of the VAT Executive Regulation. As commonly summarised, a service is zero-rated as an export when the recipient has no place of residence in an implementing state and is outside the UAE when the services are performed.
That gives two questions. Where does the customer belong? And where was the customer, or the individual receiving the benefit, when you did the work? An invoice addressed to a foreign company is not, on its own, enough.