Formula at day, breastmilk at night

Has anyone done this? We would be doing it more for him to actually be getting at least some breastmilk instead of none due to supply issues, high demanding job and not enough time to pump frequently. He has never latched so it would be more of a pump and give through bottle. For any of you that have combined formula and breastmilk in a feeding, how did you do it?! I just need advice. It’s not an option at the moment for breastmilk to be 100% of the time.