I have multiple dividends, capital gains, interest, etc from two investment accounts. can it just include the totals and send the IRS the backup through the mail?

Yes. You can enter a stock transaction summary. However, it's not advisable for dividends and interest.

You've probably explored imported from your broker to avoid the data input. Please feel free to post any additional details or questions in the comment section.

https://ttlc.intuit.com/replies/4926553

Here's a little instruct on handling a 1099 composite:

https://ttlc.intuit.com/replies/6660730