A PGCEi is an online teaching postgraduate qualification that is awarded by a UK university. A PGCE is a Postgraduate Certificate of Education and the 'i' means "International". A PGCEi on its own gives you the ability to teach in some countries, but in the UK you will also need QTS.
If you are an experienced teacher with a PGCEi, you can achieve QTS without having to do any further training via the assessment-only route. If you only have a PGCEi, you will have to complete an induction programme at a school before gaining QTS.
This route allows you to demonstrate that you already meet all of the requirements for QTS, and will be taken in a school over 12 weeks. During the 12 week assessment period you will complete an evidentiary portfolio to show you meet The Teachers Standards and undertake an intial assessment by an independent assessor. After 3 months you will be revisited and if deemed successful a formal recommendation will be made for the award of QTS.
To be eligible for the assessment-only route, you must hold a degree or equivalent qualification granted by an institution in the UK, or an equivalent degree or other education qualification granted by a foreign institution. Two years of teaching experience across two age ranges or key stages is also required.