Sales tax is money collected on behalf of the government. It could be Federal, State, County and even City tax. It could become very simple or tedious to manage it. Depending on the service or good sold what taxes have to be collected. Telephone service pays taxes at all levels, federal, state and local (county and/or city), whereas for example groceries will just pay state and/or local.
Based on the complexity of the taxes collected attention must be given to the software selected. Most Point of Sale (POS) software cannot handle multiple sales taxes. All the percentage must be added up and then defined one Sales tax that will cover all. Some will allow discriminating if the POS software is integrated with an Accounting package, in the case of QuickBooks POS.
Source: 1-StepTechnology