I’m US Citizen and my husband has only a work permit but if I want to apply for a visa for my mother-in-law and father in law, what do we have to do

To apply for your in-laws to live here permanently on immigrant visas, your husband would have to become a US citizen to sponsor them. To apply for them to visit the US, they would have to go through nonimmigrant visa application interviews at the American Consulate overseas. You could help by guaranteeing financial support and that they will leave at the end of their period of visit. Kindly note that visitor visas are given in the discretion of the consular officer. Due to the limitations of the Lawyers.com Forums, Alan Lee & Arthur Lee, Esqs.’ (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.