If you attain a CNA certification in one state and want to work in another, you are likely required to be listed on the other state's nurse aide registry.
To be listed on the other state's nurse aide registry, you may want to start by contacting that state's nurse aide registry offices to determine their process and requirements. Keep in mind these may vary from state to state. Some may call it a transfer or reciprocity or something else. Some states may have a form you fill out or have a form the registry fills out, or their forms may be completed online or by mail. You may need a certain certification before being accepted; for instance, applicants from Maryland transferring to West Virginia need to have an active Geriatric Nurse Aide certification to be accepted. Or I wouldn't know if many states have something you need to start the process before going to another registry, or if your status in one state is affected by being in another. Again, some good questions best answered by the registries of where you are and where you're going.
Also, keep in mind filling out forms for reciprocity or transfer is just that; they don't automatically grant or ensure your position at Point B when received. Even though submitting electronic applications or sending things electronically takes very little time, I cannot imagine many transfers being instantaneous or automatic. The receiving end may need to review them for approval listing before you are officially instated on their registry. You may want to ask them how long their process can take, how you find out your status, and plan accordingly so you aren't in a bind or miss an opportunity because your transfer hasn't fully completed yet. Try to be patient and flexible; yours is one of dozens they review in a day on top of other registry business they manage. That's not even thinking about any places or procedures that may still be functioning under precautions or limitations brought on by COVID (or maybe less so by inclement weather or incidents depending on time and place).