I think you mean your W-4--the document you fill out for the employer so the employer will know how much tax to withhold from your paychecks. You are not the one who fills out a W-2---in January your employer(s) issue W-2's to show how much you earned and how much was withheld for taxes.
Each employer will withhold as if your job with them is your only job. If you want more -- or less -- tax withheld from your paychecks then you may want to adjust the withholding you want on the W-4 you give to the employers.
https://www.irs.gov/individuals/tax-withholding-estimator
https://www.irs.gov/pub/irs-pdf/fw4.pdf
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
