Notice that to insert the parentheses or brackets the left and right commands are used. On your Mac from the menu bar choose Insert Equation. In this video.
Open an example in Overleaf.
You can display mathematical notations in Latex. I post very short videos to explain LaTex in details one topic at a time. The first one is used to write formulas that are part of a text. L a T e X allows two writing modes for mathematical expressions.