Allegedly, after signing a preliminary contract for the purchase of a house in Luxembourg, the notary prepares a bundle of documents required for the transaction. In order to buy the property, the buyer needs to submit a basic set of papers.
The answer depends on your current status in the Grand Duchy. Mortgages are very popular in Luxembourg, but they are usually granted to citizens and people with residence permits. It is mandatory to have an income and official employment.
It is extremely difficult to get a mortgage for an immigrant without a residence permit. Most likely, you will have to make a one-time payment with no installments.