Code point
U+2378
Glyph appearance depends on your fonts.
U+2378
SoU+2378 APL FUNCTIONAL SYMBOL IOTA UNDERBAR is a Unicode 16.0.0 character in the Other Symbol category. It belongs to the Miscellaneous Technical block.
Choose the representation you need, then copy its value.
U+2378
9080
⍸
⍸
E2 8D B8
2378
00002378
%E2%8D%B8
\u2378
\u2378
\u2378
\2378