You could just copy paste this:☑ ✓ ✔ √

or do this whole thingy

1. Find Alt code.

Numeric Alt codes for symbols are listed in Alt codes list. Check for Alt code of symbol you want to input.

2. Enable Num Lk.

You may need to simultaneously press ["FN" and "Scr Lk"] keys. That's the combination for "Num Lock" on some laptops. Look at the picture - the "Num Lk"/"Scr Lk" button is highlighted there.

3. Hold down "Alt" key.

Some laptops require you to hold both "Alt" and "FN" keys.

4. Input Alt code of symbol on Keypad.

Do this while holding "Alt" button pressed. Type Alt code on your laptop's numeric keypad. It's highlighted on the picture.

5. Release all the keys.

After you release all the keys alt symbol should be entered. If all this stuff didn't work - check if you have really enabled the "Num Lock" first. Remember that green indicator should shine near the lock symbol on your laptop's keyboard. If that wasn't the case - try simultaneously holding "FN" and "Alt" keys instead of just "Alt". That just might work.

and here's the list of characters for ALT codes: http://alt-codes.org/list/