To integrate your store with DHL, you first need to have an account:
Go to Settings > Shipping Carriers > DHL.
Enter the required details.
Click OK.
Sign up for an DHL account here.
Log in to your DHL account.
Go to General > DHL Account Information to obtain your DHL account number.
Your Account Country Code will be available on your invoices. For further details and information, you can check out their website.