how add a file in every dir and subdir

i need to put file in every dir and sub dir

i use bash on mac with brew

i tried this

for dir in \`//Users/oscarristolfi/Downloads/roma/\* . -type d\` ; do cp index.html   ; done

i' have tried but it show only echo, result

/Users/oscarristolfi/Downloads/roma/copia.sh: line 7: //Users/oscarristolfi/Downloads/roma/cerco-amici: is a directory

i try tu add a dir variable but nothing

for dir in \`//Users/oscarristolfi/Downloads/roma/\* . -type d\` ; do cp index.html  $dir/index.html ; done

I would use find instead of for.
Given that index.html exists in the current directory where you run find from:

find //Users/oscarristolfi/Downloads/roma/* -type d -exec cp index.html {} \;

Add options to cp:

• -f if you want to force overwriting an existing index.html in the target directory.
• -n if you don't want to overwrite an existing index.html in the target directory.

^{I'm not familiar with MacOS and the //Users part of the path, but I'm assuming it's some sort of link to the top of where the home directories are placed.}