no law requires employers to accept resumes or applications if there are no openings, but an employer should either keep all unsolicited applications, or throw them all away – "cherry-picking" can easily lead to disparate treatment claims with the EEOC or a state human rights agency
job applications should solicit only job-related information
if a potential question for the application will not help determine who is the best-qualified applicant, do not ask it
be sure to ask about hours and days of availability for work; let applicants know that if they indicate availability times that do not match the job posting or the job description, they may not be further considered for the position in question
at the end of the application, let applicants know that by signing and submitting the application, they give their consent for various things:
the employer may verify any information given on the form
any wrong or incomplete information can result in the applicant not being hired or, if the problem comes to light after hire, it can result in immediate dismissal from employment
the applicant agrees to submit to any job-related medical exams or drug tests that might be required
the applicant understands and agrees that if hired, employment will be at will
An example of such a statement might be something like this: "I certify that I have fully and accurately answered all questions and have given all information requested in this application for employment, and I understand that any wrong or incomplete information on the form may disqualify me for further consideration for employment or, if discovered after I am hired, may be grounds for my immediate dismissal. I understand that all such information is subject to verification by the Company, and hereby give my consent to the Company to investigate my background and qualifications using any means, sources, and outside investigators at its disposal. I agree to undergo any type of drug and/or alcohol testing that the Company may require at any time. Finally, I understand that submission of this application does not necessarily mean that I will be hired, and that if I am hired, my employment will be at will, and either I or the Company may terminate my employment at any time, with or without notice or reason."
the EEOC requires employers to keep solicited job applications for at least one year – it is best to keep them at least 4 years, in order to exhaust all possible statutes of limitations for various employment law causes of action, and the application for the successful candidate for at least 7 years; if EEOC investigates and finds that applications have not been kept, that is not only a recordkeeping violation, but also potential evidence of intent to discriminate
the State of Texas has an official employment application form (PDF) that illustrates the kinds of things that a job application should include