Hello there, @@JeanetteLeisegang.
Thanks for visiting the Community. Yes, that's true. Your employees' tax codes will tell how much tax-free income they can get in a specific tax year.
You can refer to this HMRC article for more information: Letters in your tax code: what they mean.
Additionally, we recommend that you update your tax tables at least every 45 days, or every time you pay your employees. Here's an article to guide you on how to do it: Update Payroll tax tables.
Feel free to visit again if you have additional questions. I'm always delighted to help you some more.