I don't know how to effect a credit card bill payment in kmymoney.
Plus, I don't know what exactly charge and payment mean in a credit card account.
For a credit card bill payment to be effected, I need to subtract the same amount of money from the credit card account and the bank account associated with the credit card.

Is there a way to do it in one transaction?
I don't even know how to do it properly with two transactions.

It seems to me the account you need is not a credit card account. Your card is probably a debit card. A debit card is associated with a Checking account. Transactions with a debit card are registered in that checking account. In some European countries, these types of payment have different names, such as deferred-debit versus immediate-debit cards. The only difference between those two is the date the payment is charged to the account. If there is no monthly payment at a fixed date, it's not really a credit card.

In a credit card account, a Charge occurs when you use your card to purchase something. Your account is in the red most of the time (you buy on credit). You pay your debt usually once a month by making a Transfer from a regular bank account (checking, savings). A Payment occurs e.g. if a merchant overcharged you or if you return an article, and he reimburses you.

I have a credit card that has a fixed payment date.
And I have a debit card apart from it.

By the way, thanks for the information.

When I use my debit card to pay for something I prefix the payee with DC So I can easily identify debit card transactions.
Similarly for direct debit I use DD and SO for standing orders.

So in my current (checking) account I have payments to:
DC - Asda
DD - Southern Electric
SO - Savings account.

This is the same convention my bank uses so monthly imported transactions from their OFX file match and the account reconciles no problem.

I have a scheduled transaction to record my credit card payments each month.

Works for me.

crocket wrote:For a credit card bill payment to be effected, I need to subtract the same amount of money from the credit card account and the bank account associated with the credit card.

I'm not sure I understand this correctly. If this is your monthly payment, it should be entered as a transfer from the bank account to the credit card account. This operation, entered once, will appear in both accounts. Why does the amount have to be subtracted from two accounts?