Code point
U+2551
Glyph appearance depends on your fonts.
U+2551
SoU+2551 BOX DRAWINGS DOUBLE VERTICAL is a Unicode 16.0.0 character in the Other Symbol category. It belongs to the Box Drawing block.
Choose the representation you need, then copy its value.
U+2551
9553
║
║
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E2 95 91
2551
00002551
%E2%95%91
\u2551
\u2551
\u2551
\2551