first time filing for a child

[user17757879728]

my son 15 had a summer job made 2000. I'm mailing in his taxes my question do he sign his tax or do both of us sign 

[Bsch4477]

Only he needs to sign his return. 

[Mike9241]

just him. you are not a paid preparer.  However, you should fill out the Third Party Designee section so the IRS will contact you if there are questions. 

if it was only W-2 income, that's below the Federal filing threshold, so a return would only be required to get a refund on taxes withheld. If he got a 1099-NEC, he would owe Federal Self-Employment tax, so filing would be necessary.  States have different requirements.