The Warm Home Discount is a one-off payment of £150 to help with the cost of energy during the winter. It's designed to make things a bit easier if you're living on a low income or pension.
If your electricity supplier is part of the Warm Home Discount scheme then you don't need to apply for it – you'll get the payment automatically if you or your partner receive the Guarantee Credit portion of Pension Credit, or another qualifying benefit, and have high energy costs.
Getting a Warm Home Discount doesn't affect your entitlement to a Winter Fuel Payment or the Cold Weather Payment.