1099 For Child Over 18

[Shaun Hunt]

I have my kids do work on the rentals with me.  Two are now 18+. I am learning that they need a 1099 for work completed in 2019.  Are there any hints on how to go about this?  The IRS instruction page was 13 pages in length.  I was hoping for some clearer answers as to what was needed. 

Do my kids need to apply for EIN, TIN or any other numbers?

How do I file 1099 with IRS?

What else would be helpful to know?

If my kids, under 18, make just over $12,000, with they need to file taxes?

Thanks for considering a response.