I am filing a 5129 form and i dont have any idea what goes in box 3(tax form number) and unsure about box 4(tax year ending) i guess the one I'm actually filing (2018)

If this is in regards to your 2018 personal tax return, the Tax Form Number is 1040 and the Tax Year Ending is 12/31/18

Wao. Thank you. I have been looking for the answer for about 1 hour. So just to be clear even form is 5129 the tax form is the one you give me?

Yes, the "Tax Form" its referring to in Box 3 on this Form 5129 would be 1040