I do everything that was on krita offical page and even then my drawings dont save as how It supposted too. They look a lot of darker on the phone. I dont know what to do 😔😔 Sorry for any mistakes, english isn't my first language.

That's unfortunately not a lot of information to provide a definitive answer for. First of all, does this only happen with images that you exported from Krita or do you see the same visual differences in any drawing or photo when comparing them between your computer screen and your phone?
Does the exported image still look identical to the original document in Krita when opened in an image viewer on the same computer?
What color profile are you using on your document?
What image file format and settings are you using to export the document?
Is your computer monitor calibrated well, so it would be good enough to use as reference?
Which phone do you have and what image viewer app are you using on it?
What official page are you referring to?