I don't quite understand the question. But I am assuming you are talking about postings in an accounting package...? If so, total sales for the day is credited to the sales account which includes cash and credit sales.
Then cash/ bank a/c is debited the amount of receipts actually received and accounts receivable (customer a/c) is debited with credit sales.
With respect to how taxes are recorded it varies from software to softwaare. Mine automatically calculates the taxes based on the sale and sends it to the tax account.
If you're using Sage, the easiest way to record retail sales would be in the cash register which is in the banking module on the left hand side.
Retail tax rates will be either 20% or 0% depending on what your client is selling. You will need to enter different lines for the different tax codes when entering your sales figures. You can also put in whether you received card, cash or cheque as payment.