If you do not hold a valid M-card or Annex 56 (which proves you applied for the M-card), you are allowed to enter Belgium and other Schengen area countries without a visa for a period of up to 90 days within a 180-day period. The 90 days start counting when you enter the Schengen area until the day you depart. You can use the short-stay visa calculator to calculate your days in the Schengen area. All days spent in the Schengen area, irrespective of the purpose of the trip (including tourism, family reasons, and business visits), count towards the maximum 90-day limitation.
For business trips, limited professional activities are permitted and certain formalities might need to be complied with. More details here.
When traveling to Belgium and the rest of the Schengen area, you should carry the following documentation to pass through immigration smoothly:
In 2024, the EU start to introduce its new European Travel Information and Authorization System (ETIAS) for travel into the Schengen area. The first step will be the Entry/Exit System (EES). These electronic systems will increase scrutiny of travellers' respect for the limitations on short stay visits, such as the 90-day limit within a 180-day period.