can I not use ~ when specifying a path using the cp terminal prompt?

Question

I ran this in the git bash terminal: cp 06-Stu_HTML/ ~/sandboxes/bootcamp/01-sb

and got this error message: cp: -r not specified; omitting directory '06-Stu_HTML/'

I tried to look up the -r flag in correlation with using the cp prompt, but I couldn't find anything on it. Aside from that, I was wondering if trying to use ~ when designating a path was the reason I'm encountering issues?