Why does the icon font appear jagged?

Question

Fonts

I decided to use vector icons on the site, I collected the font on the flaticon.com service, I
tried to insert it as separate svg files, with an icon size of 18 x 18, clumsiness / roughness appear.
On the iPhone they are displayed perfectly, on the desktop they are disgusting.
who faced such problem? how can it be solved?

browsers chrome, fox, win10

Answer 1

read about font smoothing MDN font-smooth