Unlike child support, spousal support is often very difficult (if not impossible) to modify after the divorce is final, so getting it right the first time is a must!
If there is no child support (and there will not be for you), the court will not take it. She can ask to have it garnished but it's not necessary if you are paying. My husband found it easiest to count and prove if he issued an actual check with that in the memo line. Even then, there is one court ordered amount that was to count as support and another check with "support" written in the memo line that the ex is claiming don't count. They do, and every lawyer she's ever had admits it, but becasue the amounts didn't get paid directly through the child support group, the child support people don't have them counted in thier calculations so the ex is saying they don't exist.
SO MUCH BETTER to have a clear record with that in the memo line so that anyone who ever questions my husband about it will be able to see... DUH... if she CASHED the darned check then it's SUPPORT. WE don't have to bother arguing that he gave a GIFT of that amount to her back when she was starting on the evil track, making the previously amicable arrangement nasty, and kidnapping the kids... yeah... sure... it was a gift.
No need for a 1099. If you do TurboTax they will ask about it and do the correct form in the right line. You'll just want to keep the cancelled checks with that year's taxes in case she fails to deal with them and fails to declare them in her return.