Hey, Snezhana !
My name is Alex, I'm a guru here at Shopify!
Hmm, I see. There is a setting in your profile with PayPal that specifically allows customers to pay without having to use a PayPal account - this isn't available in all countries, however. There are some regions where PayPal requires users to pay using an account.
I'd suggest double checking your settings in PayPal to make sure you've got the right setting there - there's more information on the exact changes you need to make in your account right over here. If that doesn't help, I'd suggest reaching out to the PayPal team directly to find out what the issue might be; they'll be able to let you know the availability in your country for this feature!
Hope that's helped! Please feel free to let me know, and you can always give us a call or start a live chat at any time. We're open 24/7 for your convenience and always happy to assist!
Alex | Shopify Guru