I am in the process of buying property and I would like to have it in my name and my 4 year old grand son name. Would it be legal to have the deed written to say my name and or my grand son's name. Thanks

There are many ways to list someone as a joint owner or owner in case of your death,
Or with right of survivialship.

The wording will depend some on where you are located. You will advise your real estate attoreny who is handing this.

Also of course in some states the contract for sale will need to list the grandchild, since some will require this to write the deed that way.

Also if there is a mortgage, they will need to be aware of a second owner

I am in the process of buying property and I would like to have it in my name and my 4 year old grand son name. Would it be legal to have the deed written to say my name and or my grand son's name. Thanks

Yes. But I suggest a joint tenancy with right of survivorship so that if, for example, you die first, it automatically belongs to your grandson, without having to go through probate.