Big refund this year.Want to decrease without having to pay.Starting a second job,single,no dependents,claim 0 for my first job.What should W4 look like for second job?

[Mark-D]

1.  Use the IRS withholding calculator at https://www.irs.gov/individuals/irs-withholding-calculator which does have ability to address multiple jobs and income sources.
2. Use the IRS Publication 15 and 15-A https://www.irs.gov/pub/irs-pdf/p15.pdf and https://www.irs.gov/pub/irs-prior/p15a--2019.pdf to calculate what each W-4 form will result in withholding, and then adjust the form values as needed so the right total amount is taken out.