How can I change plugin to give access to editor user role?

The manage_options argument you see in both function calls is a capability. That particular capability makes the page accessible only to administrators.

To make this work, you could change that to one of the editor capabilities like edit_others_posts You could also create a new capability and use that.

However, doing either will mean hacking the plugin and the next time the plugin is updated your changes will be overwritten, which is why hacking plugins is generally a bad idea

I would:

1. Think carefully about why editors need access to this global
   settings page. “Editors” are logically a “content” role, not a
   “global site administration” role, which is what you seem to be
   partially converting them to.
2. Consider whether what editors need is perhaps a shortcode or other
   simplified access to the plugin functionality.
3. If neither #1 nor #2 fit, contact the plugin author and find out why access is
   limited and whether the author would be willing to change the plugin
   code