According to the Alabama instructions:
An Alabama Resident is someone who is domiciled in Alabama. Your domicile is where you live permanently. A person can only have one domicile.
Individuals not domiciled in Alabama that maintain a permanent home in Alabama, or spend more than seven months of the taxable year in Alabama are considered to be residents.
If an individual moves into Alabama, they are considered a resident and must file a resident return reporting their Alabama source income for the time they resided in Alabama. No income earned before the time the taxpayer moved to Alabama is required to be reported. You may need to claim a credit for taxes paid to the other state if the same income is taxed on both state returns.
If you change your domicile, you must change it with the state or you will continue to be considered a resident and remain liable for income taxes.
An Alabama Part-Year Resident is any individual who moved into the state. Income attributable to Alabama is taxable on the state return. You may need to claim a credit for taxes paid to the other state if the same income is taxed on both state returns.
An Alabama Nonresident is an individual that does not maintain a permanent home in Alabama.
If one spouse is a resident and the other is not, file returns using the married filing separate filing status. To do this within your account, you can file the federal return and wait for the return to be accepted. Then, change the filing status for the primary taxpayer and file a separate return for the first spouse. The second spouse will need to create a new account and file the separate state return in that account (if required to file).
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