How do you create the symbol ≥ in ios?

Here's one way: In Numbers tap in cell, the the =, drag the "bar" of symbols to the left until you see ≥ . Select that, in the cell insert a ' (a single quote) before the symbol and tap 'return'. Then double-tap the cell copy-paste the symbol from the formula editor (not the cell) to wherever you need it.

SG

I keep a few special characters in my Notes app so that I can copy and paste them into other documents as necessary.

I originally created my Note (First line of which is Special Characters) by copying the symbols from Emoji & Symbols and in particular Math Symbols on my Mac