Is there a keyboard shortcut to move cursor from a cell in my sheet (i.e. cell) to the formula bar?
I have searched SO but cannot find answer.
(currently I leave the cursor hovering over the formula bar and left click mouse)
On Windows, the shortcut for editing a cell is F2 and if you're using Mac then it's Control+U.
With Excel's default settings, this will edit directly in the cell, the same as double-clicking the cell will.
If you want to always edit cells in the formula bar, even when you use a keyboard shortcut, you'll need to disable "Allow editing directly in cells" in the settings.
The actual settings may look different than this image for the version you are using.