Indiana State Tax Returns | Did not receive 1099s

Were you supposed to receive them? Or were they lost/misplaced?

If the amounts are too low they don't have to issue a 1099. But if they were lost you may be able to get a replacement.

Are they available on the website? Many 1099s, 1098's, and W-2's I see only exist as a PDF file. The pdf can of course be printed.

You don't mail in most 1099s. They are a reference for you to know what your bank/brokerage has reported to the IRS.

As @dave_thompson_085 pointed out, that for paper filings certain documents with withheld tax needs to be submitted. The IRS requests that a copy of 1099-R be submitted.

If you have a online account, you should be able to download them. Otherwise you should call and get a copy.

If you bank/brokerage made a mistake with income types (i.e. capital gain vs return on capital), they will mail/generate out a corrected form or you'll have to follow up with them.

Do realize that if the amount reported on any 1099-INT or 1099-DIV is below $10 USD, the bank/brokerage/mutual fund isn't required to generate the form.