All full-time employees are entitled to 28 days paid annual leave a year, so your holiday you can take could be 20 days and then bank holidays you don’t have to take as a holiday. Or you may have 28 days of holiday a year but you have to take the bank holiday days as holiday days or take them unpaid.
If you are not sure you are being given the right amount of holiday you can go here to calculate the holiday you should be entitled to.