moving from iPhone6 to iPhone8PLUS can I keep my number

You are very welcome.

No worries, all questions are legitimate. I would inform your carrier about your existing SIM card to be used on the new iPhone (there shouldn't be any problem, but your carrier might have an update to be performed on your new 8+).

Regards and best of luck.

Giulio

Yes, of course. When you activate the new iPhone, put your old SIM card (from the model 6 to model 8+)

Regards

Giulio