You have the option. However, unless you have compelling reason to file separately I would recommend to file jointly. Joint filing usually results in lower overall tax. In addition, you moved to Washington, a community-property state that can make filing separate returns even more complicated. Filing as either joint or separate is acceptable, as long as you were married on December 31,2018, even though you lived apart.
This FAQ provides additional information on this subject: https://ttlc.intuit.com/replies/3288477