How to insert a right single quotation mark?

US layout: alt/option + shift + ]

German layout: alt/option + shift + #

Use Keyboard Viewer to see which key does what. You activate it by checking its box (and the one for "show input menu in finder") in system prefs/international/input menu.

n the "Input Menu" tab of "International" system preference, enable "Show input menu in menu bar" (bottom of window). You can then click the flag in the menu bar to show the Character Palette. Find the special characters you want and use the tool at the lower-left to "Add to Favorites". Click the "Favorites" tab, and leave the window open. Move it to a corner of the screen so you can still see it when other windows are open. When you want to use one of the favorites, just double-click it in the "Characters" window. It will insert it into the application you are using.

“Zeichenpalette” sounds like the German name for Character Palette.

You might consider switching to the German keyboard layout. I'm not familiar with the German localisation of the interface, so I don't know what exactly the International pane looks like. You should turn on the Keyboard Viewer anyway, as it is a valuable tool to have for all layouts.

Instructions, relying on pictures more than text, to make up for my lack of German knowledge:

1. Open System Preferences. It has the icon of three realistic gears in a box. You can also pick the fourth item down from the top of the Apple menu.

2. Click the icon of the blue flag.

3. In this preference pane, click the third tab to the right out of the three at the top.

4. Tick the box that has a grey icon of a keyboard next to it to turn on the Keyboard viewer.

5. If you wish to try the German keyboard layout, which will place German quotes in a more accessible position, scroll down and tick the box with a German flag next to it.