problems with the design of my website in the mobile version

Hey yas28,
Do you mean that the titles don’t fit on a single line like this:

you can adjust the font size for mobile at styling ▸ font size and click the icon for the phone and then set the size you wish

To see a better display of your site for mobile when you are editing, try opening your site in another tab and use the Dev Tools Responsive Design Mode

Best regards,
Mike

Hi,
To add a screenshot please try using an Screenshot service and pasting the image URL in your post.
To center Olha Karpi on small screens

Try this CSS in your Enfold Theme Options ▸ General Styling ▸ Quick CSS field:

@media only screen and (max-width: 425px) { 
	#top #main .av-large-testimonial-slider .avia-testimonial-meta {
	display: flex;
    flex-direction: column;
    align-items: center;
}
}

After applying the css, please clear your browser cache and check.

Best regards,
Mike