you don't put it on form 1040. if the fair market value of what you gifted to any of your children is more than $15,000 in a year (2020 ad 2021 amounts) you must file a gift tax return reporting those over the limit
In general. If you are a citizen or resident of the United States, you must file a gift tax return (whether or not any tax is ultimately due) in the following situations.
If you gave gifts to someone in 2020 totaling more than $15,000 (other than to your spouse), you probably must file Form 709.
Certain gifts, called future interests, are not subject to the $15,000 annual exclusion and you must file Form 709 even if the gift was under $15,000.
Spouses may not file a joint gift tax return. Each individual is responsible for his or her own Form 709.
You must file a gift tax return to split gifts with your spouse (regardless of their amount) as described in Part 1—General Information, later.
If a gift is of community property, it is considered made one-half by each spouse. For example, a gift of $100,000 of community property is considered a gift of $50,000 made by each spouse, and each spouse must file a gift tax return.
Likewise, each spouse must file a gift tax return if they have made a gift of property held by them as joint tenants or tenants by the entirety.
Only individuals are required to file gift tax returns. If a trust, estate, partnership, or corporation makes a gift, the individual beneficiaries, partners, or stockholders are considered donors and may be liable for the gift and GST taxes.
The donor is responsible for paying the gift tax. However, if the donor does not pay the tax, the person receiving the gift may have to pay the tax.
If a donor dies before filing a return, the donor's executor must file the return.
Gifts to people do not go on your tax return. They are not deductible.
You don't report gifts given or received on your personal tax return. If someone gives more than $15,000 to any one person, the giver might have to file a gift tax return form 709 to deduct the gift off their lifetime 5.43 million dollar exclusion but there won't be any taxes due.