Yes, this is a brand new credit and you need to file a simple state form to claim it. If your income is less than $73k, use one of the options through IRS Free File that includes state returns for free:

https://apps.irs.gov/app/freeFile

I'm a volunteer with VITA, a free tax preparation program and we can also e-file both the federal and state returns for free. You can look up the closest location to you here:

https://www.irs.gov/individuals/free-tax-return-preparation-for-qualifying-taxpayers

Because this is so new we still are learning what is required for this credit. From what I understand you should include your state driver's license information and if you have children they need to be listed on the state form. You also need to answer a couple questions about residency (must have been a WA state resident for at least 183 days in 2022). There are some optional demographic questions.

You can find a list of supported tax filing software here; most of them have options through the IRS Free File program, so look there for free state returns.

https://workingfamiliescredit.wa.gov/apply/apply-using-tax-preparation-software