How can I download Chrome on my iPhone?

If you're talking about this app:--> https://apps.apple.com/app/google-chrome/id535886823, you can download it from AppStore.

If you mean something different, please specify your needs better.

Thanks and regards

Giulio

Instructions from Google are here:

https://support.google.com/chrome/answer/95346?hl=en&co=GENIE.Platform%3DiOS

Read this document to learn how to download apps and games on your iPhone or iPad

Download apps and games on your iPhone or iPad - Apple Support

Did you search for it on the App Store?