Working tax credit was available to provide extra help for people on low incomes. However, it is being replaced by Universal Credit and is now only available for new claimants who get the severe disability premium or got it in the past month and are still eligible for it.
Universal Credit is available for people of working age who no longer qualify for working tax credit and pension credit is available for people who have reached state pension age who no longer qualify for working tax credit.
Yes, you can continue to claim your working tax credit in the usual way. However, if you stop your claim and then try to make a new claim, you will be unable to do so as working tax credit is being replaced by Universal Credit.
More information about working tax credit can be obtained from the Government information website.