The three Japanese writing systems
Japanese mixes three scripts. Hiragana (あ い う) writes grammar endings and native words, katakana (ア イ ウ) writes foreign loanwords, names and sound effects, and kanji (愛 夢 心) are characters borrowed from Chinese that carry meaning. A single sentence often uses all three.
Each kanji usually has several readings. The labels above give a common meaning and reading, so 心 is kokoro (heart, mind) and 夢 is yume (dream). If you want a kanji for a tattoo or a logo, check it with a native speaker first, since meanings shift with context.
Why ツ and ッ look like smileys
The katakana ツ (tsu) looks like a smiling face, which is why it is the face in the shrug ¯\_(ツ)_/¯. The small ッ is not a separate sound: in Japanese it doubles the next consonant, as in カップ (kappu, cup). ㋡ puts ツ in a circle for an instant smiley.
シ (shi) and ツ (tsu) are easy to mix up. In シ the two short strokes sit on the left and the long stroke sweeps upward; in ツ they sit on top and the long stroke sweeps down. The same trick separates ン (n) from ソ (so). Find more faces built from these characters on the kaomoji page.
Japanese signs and how to type them
〒 is the Japanese postal mark, written before postal codes, and 🔰 is the beginner mark that newly licensed drivers in Japan display on their cars. 々 repeats the previous kanji, as in 人々 (hitobito, people), and 💮 is a mark Japanese teachers use for good work.
To type Japanese yourself, add a Japanese keyboard in your settings: Microsoft IME on Windows, Japanese Romaji on a Mac, or the Japanese keyboard on iPhone and Gboard. Type a word in romaji, such as "sakura", and press Space to convert it to 桜. For Chinese characters with pinyin, see Chinese symbols.