Employment Contract Probationary Period If A Employment Contract Probationary Period Expires, Does It Role Into A Permanent Contract?

If a employment contract probationary period expires, does it role into a permanent contract? - employment contract probationary period

I finished my internship for six months in February 20 and received no notice of my boss if I had a permanent or not, on 6 March was evaluated and told my probation extended 3 months. Is this possible or must be reported before the end of the initial trial period?