Yes. Overseas residents with non-UK addresses can sign up and enrol for HMRC Online services. When you enrol you'll have to enter specific HMRC reference information that identifies you or your organisation.
You won't have to enter a UK postcode, unless you are registering (signing up) as a Corporation Tax agent or a PAYE employer.
Once you've enrolled to use the online service you will have to wait for a confirmation letter containing an Activation Code before you can use the service. This can take up to 21 days to reach you.