Any person desiring to become a candidate at any election which may be held under this part for the office of mayor or associate commissioner may become such candidate by filing in the office of the mayor or commission of the city, if at the first election of the commission under this part, or with the commission at any subsequent election, a statement of candidacy, accompanied by affidavit taken and certified by the mayor or by any member of the commission, or by a notary public, that such person is duly qualified to hold the office for which he or she desires to become a candidate. No person shall be eligible for such office unless he or she is over the age of 21 at the time he or she becomes a candidate, or unless he or she is qualified to vote in the election at which he or she shall be elected. The statement shall be filed at least 20 days before the day set for such election, and shall be substantially in the following form:

"State of Alabama, Houston County, I, the undersigned, being first duly sworn, depose and say that I am a citizen of the City of Dothan in the state and county and reside at ________ in the city; that I desire to become a candidate for the office of _______ (inserting mayor, associate commissioner for Ward 1, 2, 3, or 4 as the case may be) in the city to be held on the day of _______; that I am duly qualified to hold the office if elected thereto, and I hereby request that my name be printed upon the official ballot at the election. (signed) _______ Subscribed and sworn to before me by _______ on this the _______ day of _______, 20__, and filed in this office for record on that day. (style of officer)."