We recommend this format:
However, our system is very flexible and allows for the most common formats, including:
32498 xx xx xx
32498 / xx xx xx
We do not support local number formats (numbers without countrycode), except for Belgian numbers.
Also, if you are using excel, take care of the formats that have a leading zero, such as 0498xxxxxx. Excel might detect that this is a number and format the cell as a mathematical number. Mathematical numbers cannot have a leading zero, so it might convert it to 498xxxxxx. This is why we recommend using 32498xxxxxx