Setting value while adding new entries to lookup field

Setting value while adding new entries to lookup field

I have a question regarding this process:

If I set a value for a lookup field while adding new entries, and the form it looks up to has code On Load (Create), does the On Load (Create) code trigger and override the set values? Seems like it does.

If so, is there a way to know when a form is being opened e.g. On Create vs On Create Set Value, so that I can control how the opened form is pre-populated?