I have read the documentation and I am aware that picklist values need to use ISPICKVAL in the formula
I want this formula to show that If the status is 'A' or 'B' it will show the days (in numbers) for the first date if it isnt any of those statuses it will show the second.
IF(ISPICKVAL(Status, "A") || ISPICKVAL(Status, "B")), Date1__c - TODAY(), Date2__c- TODAY()
How do I let the system choose whether to show the result of the first or second working out?
IF()
), this formula looks fine to me. If you're getting an error message, you should edit your question to include the full text of the error (don't try to paraphrase it).