What are the residency obligations for those filing I-485s?

Given the fact your I-140 petition is approved and assuming a visa number is available, you and your spouse, if physically in the U.S., can both file your applications for Adjustment of Status on Form I-485. You can also file for an Employment Authorization Document (EAD) and a travel document known as Advance Parole for both of you, all of which would take at least 90+ days to be issued. Once issued, your spouse would be authorized to work in the U.S. for any employer, as well as to travel in and out of the U.S. on the Advance Parole. If she still has a valid H-4, she would still be able to travel in and out of the U.S. on her H-4 as well. There are no other residency obligations.

She must be present in the U.S. at the time of filing I-485 and for biometrics. Once her advance parole document is issued (about 90 days from the date USCIS received her I-485), she can use it to travel outside the U.S. Ideally, she should maintain H status until the I-485 is approved and enter the U.S. on H visa rather than advance parole. Once green cards are issued, you must intend to reside in the U.S. as your primary home and otherwise maintain ties to the U.S., such as filing taxes, keeping a home, family, assets, etc. in the U.S. If your wife intends to depart for longer than 1 year, she must obtain a reentry permit that will allow her to depart the U.S. for up to 2 years but must still maintain ties to the U.S. as outlined above. Reentry permits may be extended.

Your wife must be physically in the U.S. when you file the I-485. After her status is adjusted and she holds a green card, then she could come and go as she needs while you are maintaining your residency. If she cannot come and go every year, she may wish to obtain the reentry permit that would allow her to stay out of the country for 2 years. However, I would think she will come in to be with her husband as much as she can each year, which means she does not have to do anything other than to travel every few months. There is no time limit of how long she must be physically present in U.S. unless it is her intention to apply for the citizenship after 5 years. In that case, she must spend 30 months out of 5 years to be eligible.

You can choose to have consular processing or adjust in the U.S. If you choose to adjust in the U.S. (ie. I-485 process), then you can also file for an advance parole and work permit during the processing time, which would allow her and you to travel back and forth during the I-485 processing time and also work in the U.S. without restrictions or dependence on your H-1B.

She must be here to file the I-485 and then return again for fingerprinting. She can travel on the H-4 but I suggest also applying for advance parole and use that when it arrives (approximately 90 days). As an LPR she must intend to maintain her home here. If she needs to travel for an extended period of time, she should file for a reentry permit, keeping in mind this will likely delay her final eligibility for U.S. citizenship if this is of interest.

Once the I-485 is approved, she is required to live here as her primary home and file U.S. tax returns. If she cannot because of commitments in Canada, she should file a reentry permit that allows her to be out of the country for up to two years. This can be extended.

The general rule for any applicant who wants to obtain an immigrant visa through I-485, Application to Adjust, is that he or she must be living in the U.S. Otherwise, anyone living outside the country must go through consular processing in the country where they live, including Canada. In this scenario, since she has an H4, she should be able to stay in the U.S. so as to adjust. Advisably, consult your attorney.

You must be in the U.S. to file an I-485. You can only leave once you have been granted advance parole. You may wish to consider filing an I-824 instead.