If you are submitting income documentation for a dual income household, you will be asked whether you filed individually, or jointly.
If you and your partner filed individually, there will be separate screens for uploading each income earner's income documents. Income documents for two separate people do not need to be submitted on the same screen.
If you are filing jointly, and you have a form 1040, that will be sufficient, and you will not be prompted to upload any additional documentation, unless you indicate that you have received Disability or Social Security Benefits. In this case, you will be prompted to upload your awards letter.