Check your contract and talk to your employer as they should be able to tell you what they will be deducting at source and passing on to the Ghana-an Tax authorities.
Years ago, when there was more money freely sloshing around, this kind of tax was often sucked up by the companies but these days they are more likely to pass the buck to your account.
Far better to clear this up at an early stage, with those that credit your account, than face a shock later down the line.