You do not type it from a keyboard; you copy it. Press the copy button above and paste it into any app. That is the whole point of Unicode styled letters.
Where can I use the Sans Bold Italic J?
Anywhere text is accepted: Instagram bios, TikTok names, Discord, WhatsApp, gaming profiles and documents. The full Sans Bold Italic alphabet is linked above.
What is the Sans Bold Italic letter J?
It is the letter J rendered as the Unicode character ๐ (code point U+1D645), part of the Sans Bold Italic styled alphabet. It is a single character you can copy and paste anywhere.