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 Serif I?
Anywhere text is accepted: Instagram bios, TikTok names, Discord, WhatsApp, gaming profiles and documents. The full Sans Serif alphabet is linked above.
What is the Sans Serif letter I?
It is the letter I rendered as the Unicode character ๐จ (code point U+1D5A8), part of the Sans Serif styled alphabet. It is a single character you can copy and paste anywhere.