Let’s use a £30 credit card repayment as an example.
You have two transactions: 1 x “- £30” from your current account and 1 x “+ £30” to your credit card.
A payment is the negative (- £30) transaction from your current account.
A repayment is the positive (+ £30) transaction to your credit card.
This advice was written for people using Money Dashboard – https://my.moneydashboard.com/