What happens when I minify my HTML in SEO terms? I mean, I minified my HTML which means that every
<meta... /> tag is being placed on one line.
Will this affect my SEO at all?
Only in the sense that your page will download faster and Google gives you points for that because a faster page load is a better user experience. Otherwise, minimizing your page has no other impact.
There are many tools available for minification.
If you’re running any CMS, you can take advantage of the
minification by many plugins.
Google watches code. Not spaces between it.