Are there any quick way to display underline in input field not only on select, but all the time?
Although I don’t understand why you’d want to do that, you could force in CSS/SCSS to underline every .input field (border-bottom: 1px solid #color or such).
Thank you! I suppose there is no ionic native solution for it?
Well, no native CSS class no, but modifying CSS/SCSS is “native”, it’s just Ionic comes with a basic style for both android and iOS, no more, no less.
Got it. Ok, thank you 
You’re welcome If you need to modify this at app scale, you can modify it on your project’s theme stylesheet (see docs below).