Looking for MyRent and stamping contract

Sorry for diseturbing you but i would like to get a small help from you to let my wife know where is My Rent or how we will make the Contract stamped

The official registration of your rental contract is done by the landlord. According to my understanding of the regulations, depending where you live this is either a strict requirement (in Flanders) or you have to officially request the landlord to do so via a registered letter (in Brussels). You should look up information depending on the region you live since rules differ for housing.

When it is registered it will show up on MyRent platform: https://financien.belgium.be/nl/E-services/MyRent
You can look up how to login, either using the Its Me app (that links to your bank account) or if you have a eID reader. More info can be found online. Good luck!