can i download itunes on a mac?

That will depend on the macOS version the Mac is running.

If its running macOS 10.14 Mojave or earlier it has iTunes built in.

If its running macOS 10.15 Catalina or later then you use Finder instead.

doggy6 wrote:

I need to erase all the content from my iphone but its not letting me so im trying to do it through my computer but i need itunes

you use finder on a mac.