Customize menu local task links I am looking for a way to customize 'edit', 'view', 'delete' links.

I use bootstrap theme, but i use bootstrap v4 styles for it. I want to add 'nav-link' class to each link.

And find a way to display somewhere, not just below post title.

I couldnt find a tutorial about it. Where should i look for this? template parts (twig) or themename.theme file?
For preprocess function you can use HOOK_preprocess_menu_local_tasks(&amp;$variables) {... where HOOK is the name of your active theme.
And for template suggestions you need to enable debugging and see with inspect element, as usual it must be menu-local-tasks.html.twig