I’m in the process of applying for an H-1B visa. I have a wife and two small children. It’s very inconvenient for them to travel all the way to the U.S. consulate, and if for some reason I’m denied, it’s a double waste of time. Can I attend the interview first and have them do so after I get my visa?
In most cases, only your spouse and children age 14 and older must attend the visa interview. For children under 14, you simply need to take their passports and application materials with you when you appear for your interview.
Be sure, however, to check the application procedures at the consulate where you will apply to verify that children under 14 do not need to accompany you. Some consulates do require the children to appear in person, regardless of age.
For your wife, yes, it's possible for her to apply at a later time. This also applies to any children if they need to attend a visa interview (up to age 20; upon reaching age 21, children are not eligible for dependent visas).
When your family members apply on their own, they simply will need a copy of your H-1B visa, a copy of your H-1B approval notice (Form I-797 Notice of Action), birth and marriage certificates showing their family relationship to you, and a letter to verify your employment. And, of course, they need their passports and visa application materials.
The only advantage to applying for visas at the same time might be if there are questions about your employment. Nevertheless, if your spouse or children are not familiar with your work or employer, they may not be able to answer questions the consular officer may have.