OK so I'm guilty of showing off !! Rogerr - this all started on yesterday's 'Riddles' Q280676 when I innocently used the � symbol - now I'm paying the price!
Anyway, as I understand it, the character set we all use consists of 256 symbols, most of which you will recognize as alphabetical or numeric as shown on your keyboard. However, it's sometimes useful to get to the hidden ones, either for special effects ♥ ♦ ♣ ♠ or for serious stuff √ � ♂ ♀ Σ, etc.
To gain access hold down the ALT key (don't let go), then press "1" on your Numeric Keypad on the right hand side (it won't work with the normal numerals above QWERTY). Now release the ALT key, hey presto! ☺☺☺☺☺
ALT 0189 = �, ALT 14 = ♫, ALT 225 = �, and so on.
If you have the patience you could make up a list and print out a table for reference, or refer to the back of an old DOS manual, or search the Internet - I can't remember whether these are called ASCI or ANSI character sets. I do know that if someone in Brazil for example is reading this message, the characters are unlikely to appear the same as in the UK because they would probably be using a different character set and the codes wouldn't all match up.
Of course if you are writing a letter in MS Word then you don't need to faff about like this - just click on 'Insert' at the top of your screen then select 'Symbol'. You'll see all the character sets and their options. Now why didn't I think of that . . . .
Regards also to Alibobs and Se�or Crofter. ja