Well sadly the 2 characters you just showed can't actually be used at all, but usually to get special characters in the game, you just have to copy and paste them. If you look up ascii characters or codes in Google and you find one you'd like to use, you literally just have to highlight them, copy them and paste them into the chat/guild name/your profile, wherever you want to put them.
Obviously if a character doesn't show up in the game, it will just show up as ?.
Mazuiko & Synkronized (ɔˆ ³(ˆ⌣ˆc)
Te amo! ♥