Split Terminal Pane

Apple's Terminal application only supports horizontal splitting into panes with each press of ⌘+D and the ⇧⌘+D to undo the last pane creation. There is no vertical split screen in the Terminal, and no apparent keyboard shortcuts to jump between the split panes, other than ⌘+T to change the split pane into a tab.

Get iTerm2

https://iterm2.com/

it can do that and so much more

Or use tmux. You can install tmux via Homebrew https://brew.sh

you can google tmux, plus there are a lot of YouTube video demos available.