How can I draw wires that are vertical, horizontal, and have 90 degree bends?
There is no way to directly specify using only horizontal and vertical wire lines, with 90 degree corners.
If you have “Align to Grid” turned on (checked) in the View menu, then any bend points you put in wires will be on the currently defined grid. The grid size is also set on the View menu. In the default configuration, click and drag anywhere in the middle of a wire will create a sharp bend. If parts are positioned with Align to Grid on, and the bend is also created with Align to Grid on, it is easy to get clean 90 degree corners. At least with most parts. If the parts themselves do not follow the rules about aligning connections to the normal grid, it becomes more difficult. Setting the grid size smaller can help in this case, with more care needed in the manual corner positioning.
In an alternate configuration, you will need to hold down the control key while click dragging to get the sharp corner.
It’s a bit out of date, so some things don’t work.
https://fritzing.org/learning/full_reference/keyboard-mouse/