Since cash is an asset, increases in cash (income) are Dr entries, while reductions in cash (payments) are Cr entries.
Payments
When a cash payment is made, cash decreases, so we Cr cash with the amount of the payment. The corresponding Dr is to the relevant expense or fixed asset (increase an expense or purchase of a new fixed asset).
Receipts
When cash is received, the cash balance increases, so we Dr cash. The corresponding Cr is to the sales or other income (increase income). It could also be the disposal of a fixed asset.