How can I resend a 1099 from 2019?

I can not answer that, but for the future you should keep a copy of any document you send to the state or the IRS in pdf form

It's my pleasure to help you resend your contractor's 1099 from 2019 in QuickBooks Online (QBO), @dinamande.

When you use our 1099 E-File Service in filing your 1099s from 2019, you'll have the option to recreate them through the Vendors menu. You can either print or download a PDF file of the form and manually resend the copy to your contractor.

Here's how:

1. Go to the Expenses menu.
2. Select the Vendors tab.
3. Click Prepare 1099's. Either follow the on-screen instructions or press the Back button until you're on Step 4, depending on where you left off.
4. Choose the filter menu (funnel icon) in the top-left of your Contractor list, and choose the Tax year you'd like to prepare (2019). Then, click Finish preparing 1099s. 
5. In Step 5, click the I'll file myself or Print and mail button.
6. On the Print 1099s page, ensure the 1099 form is selected. 
7. Select Print sample on blank paper. 
8. On the print preview page, you can either proceed with printing the form or download a PDF copy.

Here's an article to further guide you in preparing and filing your Federal 1099s with QBO: E-file through the 1099 E-file Service in QuickBooks Online.

Also, I'm adding this article to answer the most frequently asked questions about the 1099 form: What is a 1099 and do I need to file one?.

Please don't hesitate to reach out to me here for any additional assistance. Thanks for coming to the Community, wishing you and your business continued success. Take care always.