Can you buy index funds in Coinbase?

Excuse me, I was wondering if you could clarify something for me. I've been looking into investing in index funds, and I noticed that Coinbase is a popular platform for buying and selling cryptocurrencies. However, I'm not entirely sure if it's possible to buy index funds through Coinbase. Could you please enlighten me on this? Are index funds available for purchase on Coinbase, or would I need to look into other platforms or options for that purpose? Thank you in advance for your help.