Hi @esvalkunaite ,
If it is only the screen that is broken and the phone hasn’t suffered much more damage it is preferable to try and fix it, if possible.
Here’s a link to a [https://www.youtube.com/watch?v=GJXgtJlquhg|video] that shows how to replace the screen on your phone.
Replacement screen assemblies are available online.
Just search for ''Huawei P20 LCD screen'' to get results for suppliers of the part.
If you find doing the repair yourself too daunting, contact a reputable, professional mobile phone repair service (or two or three) and ask for a quote. You should know the cost of the part by then and coupled with the quote will help you decide if you want to go ahead and have it repaired or not.