You can anonymously report abusive posts and comments, and also abusive accounts. You can also privately reach out to the person being targeted if you feel comfortable doing so
Well done, you are correct!
As a bystander, you can report all kinds of abusive behavior such as bullying or harassment. Whenever you report abuse on Instagram, your identity is always protected to keep you safe. Connecting privately can really help, as you don’t actually know if the person wants or needs support - but it’s nice to offer!