If you have had to cancel a holiday due to the Coronavirus pandemic, in the first instance you should take this up with holiday provider.
My understanding is that for ABTA and ATOL protected holidays you are able to contact your holiday provider directly about refunds and re-booking, however I understand that this is not likely to be applicable in many cases. If the holiday provider does not offer these options then you should contact your travel insurance provider.
Regarding, compensation this would as always be done through the channels of either insurance. The Financial Conduct Authority rules require insurers to handle claims promptly, provide timely information on a claim’s progress, not reject a claim unreasonably, and settle claims in good time once terms are agreed.
If you feel you might be entitled to compensation from your holiday provider outside of the package travel regulations, it might be advisable to talk to Citizen’s Advice about your rights as a consumer. Contact details are available at https://www.citizensadvice.org.uk/consumer/.