The programmes that qualify for the Honours Programme have set their own criteria to determine which students qualify to take part. Further information can be found on individual degree programme sites.
In most instances this boils down to P-in-1 (all of your credit points from the first year are achieved in one year) with an average end grade of 7.5 or higher. It is also extremely important that you’re motivated and prepared to work for it.
Take a look at your own faculty on the faculty programme for exact criteria. You will normally receive an invitation if you meet the criteria. Part of the selection procedure includes a letter of motivation and interview.