Typical path: Pay → Tax Withholding → Federal W-4. Menu names vary by employer, so each step below tells you what to search for if a label differs.
Sign in to the self-service portal, open Pay, select Tax Withholding, edit the federal W-4 section, enter only the steps from your W-4 plan, and submit. The change usually takes effect within 1 to 2 pay periods. Verify it on your next paystub.
Use your employer self-service login. Complete any multi-factor step, then open the employee portal home screen.
Select Pay (sometimes labeled Pay & Tax or My Pay). This is also where you view paystubs — keep a recent one handy for reference.
Choose Tax Withholding (sometimes labeled Tax Elections or W-4 Information). You should see your current federal and state elections.
Select Edit next to the federal W-4. Review your current elections first so you only change what your plan requires.
Type your Step 4(c) extra-withholding amount (per paycheck) or Step 4(b) deduction figure (yearly). Check Box 2(c) only if your plan calls for it on this job.
Submit the change and save the confirmation. Check your next paystub FIT line — if nothing changed after two pay periods, ask HR whether the update was received.
Run the free check, then unlock your per-paycheck Step 4(c) amount.