Asana doesn’t offer a checkbox type of custom field which is typically offered among available form field types, but no worries–you can easily simulate one in Asana as follows:
Create a single-select type custom field with a name like Approved, Submitted, Nonprofit?*, Hot, Critical, or whatever attribute you want to track.
Instead of specifying the more typical option values of Yes and No, just specify a single option value, which often may best be served by a simple emoji (or for Hot or Critical, perhaps instead), or any value you like. I think it looks best to designate the first color (light grey) because no extra attention will need to be called to this field:
One caveat: If you need to report on the unset state of this attribute in Dashboards or Universal Reporting, I recommend you test first. Reporting on the “checked” value is not a concern, but reporting on the “unchecked” value may pose a problem because no actual option exists for that state using this approach. In that case, you should use two option values, not one.
For full consideration of using this tip to indicate priority, see also: