The most straightforward way is to contact LATAM customer service by phone or live chat 📞 They can verify your identity with personal information (name, last name, date of birth, email) and give you direct access to your booking without needing the code. Plus, they can resend all the documentation to your new email, including the boarding pass if it's already available.
If you'd rather try it yourself first, search your current email really carefully (even in weird folders like promotions or updates) because LATAM definitely sent that confirmation. The thing is, sometimes those emails arrive with a generic subject line and people just ignore them. But if it really doesn't show up anywhere, then you'll need to call.
One important thing nobody else mentioned: if your flight is coming up soon, don't wait too long because customer service can get swamped during peak hours 😅 Better to call early in the morning or use the web chat. Also have your ID or passport handy because they're going to ask for it to verify you.