Composition scheme for photocopy/xerox

I think photocopying is regarded as business for the purpose of GST.

Yes, you may opt for composition scheme up to a turnover of Rs.1.5 cr (unless you don't fall under special category states)

After last amendment, even service providers having turnover up to ₹50 lacs can opt for composition scheme.

Threshold limit to trigger registration is 40 lacs (for business) and 20 lacs (for service providers). Once you cross the limit, you need to register under GST and choose composition scheme (instead of regular scheme) if you want to opt for composition.