This is a serious question for any couple facing the challenge of obtaining a marriage-based green card. Usually, USCIS will look for both financial as well as personal joining of your lives.
This can look like jointly filed taxes, joint bank accounts, one of the spouses being an authorized user on the other's credit card, shared utility accounts, naming a spouse as a beneficiary on insurance, sharing a car title, photos with family and friends at different occasions and events, evidence of trips together, purchases made together or for one another, exchange of texts or emails, among many other types of evidence. Whew - that's a lot of evidence to collect!
You may or may not need all of these types of evidence, and you may or may not even have this type of evidence. This is where having a professional evaluate the evidence that you do have can be beneficial. Each couple is unique and the type of evidence that will show USCIS that it is a genuine relationship can vary. The aim should be, however, to demonstrate the intertwining of your lives, to some extent financially, and certainly personally.
In addition to looking for affirmative evidence that the relationship is real, USCIS will look for some things that they consider to be warnings, or "red flags," of what might be a fraudulent marriage. This might include a very short relationship before marriage, or big differences between the couple, whether that is age, culture, religion, language, or some other variation. Of course, these types of differences do not necessarily mean that your relationship is not authentic! But you will likely face more challenges with USCIS persuading them to see your relationship in the genuine light that it is. Affidavit letters, or letters written by friends and family can come in handy in these situations. Having an advocate on your side to bring in more nuanced or atypical evidence can help too!
