If you are an AutoCAD user, you must be familiar with these keys to create symbols.
You might be looking if Revit has the same keys for the symbols. The answer is Revit doesn’t have them.
You need to use an external tool from Windows: Character Map.
Using Character Map
You can open Character Map from Windows start menu> All Programs> Accessories> System Tools> Character Map.
In Character Map, change the font to what you want to use. Then find a symbol that you need. Click the symbol.
Click Select to move it to Characters to copy field. You can add multiple copies of character to this field. Then select Copy to copy the symbol to Windows Clipboard. Then you can paste it in any software that you use, including to Revit text.
Opening Character Map and copying the symbols might be a tedious task. If you are using a keyboard with a numeric keypad on the right side, you can use keystrokes. So if you are using a laptop, then you can use this method.
Note that on the bottom right corner; Character Map also shows the symbol keystroke.
It means you can hold Alt key then press 0248 to create this symbol when typing on any software. It will be useful to memorize most frequently used symbols. Or print the symbols dan place it near your monitor so you can see it.
You can also refer all the symbols here: Special Characters – Alt Keyboard Sequences.