Do i need to do anything for gift tax for sons 529 for 2024 taxes?

Q. Do I need to do anything special on my tax return since we contributed more than $18,000?

A. No.

Nothing about a gift is reported on your regular income tax return (form 1040).  There is a special form for gift tax reporting, but you are under the $36K, so you do not need to file form 709.   Furthermore there is something called super funding for 529 plans that allows you to contribute up to 5 years worth of contributions, in one year, and still not have to file a gift tax return. 

Super funding https://www.savingforcollege.com/article/10-rules-for-superfunding-a-529-plan

"Gift Tax" is somewhat of a misnomer.  Even though a gift tax return may be required, very few people ever actually pay federal gift tax. The purpose of the gift tax return is usually only to document a reduction in the allowable estate tax exemption.
See https://turbotax.intuit.com/tax-tools/tax-tips/Tax-Planning-and-Checklists/The-Gift-Tax-Made-Simple/INF12127.html  

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From a joint account the gift is considered to be made 1/2 from each of you so you don't need to do anything.