linux shell script how to get date string code example

Example: fomat date output

[me@macos ~]$ date '+%Y/%m/%d %H:%M:%S'
2020/05/09 13:20:2
[me@macos ~]$ date -j -v +3d -f "%b %d" "Feb 10"
Thu Feb 13 12:47:10 PST 2020