How can I call JS-file on any page? Magento 2.2.6

Question

I have a custom JS file. But when I try to call it - it doesn't work.

I use that code on content -> pages -> my_page:

<script src="My_site/file.js"></script>

It's just an image-slider. It includes css, js, and html files. On others CMS it works well.