When you create a company in BUSY and enable the GST / VAT feature, then the default Sale / Pur Type and Tax Categories will be created.
You can use the tax categories while creating items and use the Sale / Pur Type during voucher entry and tax will calculated.
Further, for payments you can record the payment voucher by using these steps:
Step 1: Open your company then go to Transaction menu.
Step 2: Select Payment voucher and click to Add.
Step 3: Enter all the necessary details such as Date, Vch Number, Account, Amount, etc and save the transaction.