How to make the title of the menu item fit?

In your template styles, look for "cover" and click to see options, at the bottom, you will see "center" you can change that to left, center, or right.

If you look further down, you're also able to edit the size of the font.

You did not understand. I'm talking about "..." in the menu. How to fit the whole word? See screenshot

I did not. 

That seems unlikely to be able to do that unless the font is smaller or the space between the icons is wider.

I've had to just use shorter words or abbreviations.