You must have had smear results that came back as abnormal before the colposcopy presumably. Your letter means that the biopsies showed up some kind of changes - normally they tell you what level (e.g. mild moderate or severe)
What they do next depends on the level of abnormality. If it's mild, they will most likely watch and wait as these often sort themselves out. If it's moderate or severe, they will want to treat it. I received an appointment for treatment with my biopsy results.
If they haven't explained it too well, I'd give the colposcopy unit a call and ask them what it means, and what happens next