Making website mobile compatible

Many themes these days are responsive and adjust themselves to fit a variety of screen sizes. At https://www.ads-software.com/themes/tag-filter/ check “responsive-layout”.

If you already have your preferred theme, but it is not responsive, there are a few plugins you could try, like https://www.ads-software.com/plugins/wptouch/ and https://www.ads-software.com/plugins/wordpress-mobile-pack/