The provider for your corporate catering packages must be able to accommodate the number of people that are coming to the event. This gets progressively harder as the number rises.
At the same time, they should be able to provide the complexity of food that the occasion calls for. For example, a formal dinner meal is likely to need more preparation compared to an casual breakfast meal.
The kind of people attending must also be considered. VIPs will expect a higher level of quality compared to rank and file employees. They may also have dietary restrictions so having vegetarian, gluten-free, and kosher-friendly options is ideal.
Of course, you need to make sure that their rates and your budget can match. It may be possible to craft a menu that would satisfy both. Set a meeting with a few catering candidates to find the best partner.