Legal Question in Criminal Law in Washington

Depends on how the case ended; If you were convicted, then there are probably some probation conditions. Those wouldn't normally include staying in the state, but can sometimes include having to get probation approval to leave the state.

If the case was resolved with a deferred prosecution, or a diversion agreeement, then you are probably free to go. I'd need to review the document to tell you for sure.

And if the case was dismissed, you have no issues at all.

Depending on how the case was resolved, something may show up on background checks when you are applying for jobs, or school, or whatever.