I have turbo tax loaded on my imac. I need to delete a form. I have no idea how to do that

You haven't said which form so here are steps to delete a Form W2 (the steps are the same depending on the form you wish to delete - just substitute the form you wish to delete for W2).

• Load up your tax return on your computer
• Switch to "Forms" mode - the icon in top left corner of your program
• You should now see a list of the forms in your return on the left-hand side of the program
• Find the Form W2 you wish to delete and click on it
• This should bring up the W2 form in your active window
• Click on the Forms option on your menu (top of your screen you should see your Apple icon, then TurboTax, then File, Edit, View, Forms, Easystep, Flags, Window, and Help - click Forms)
• There should be an option to remove the W2 form from the dropdown menu under Forms

Note:  If you have trouble deleting the form (i.e it pops back up), then you may need to delete something out of the interview.  Comment back if this happens with more details.

I had the same problem. 

Click on forms on the upper left side once you are in your Turbo Tax return. 
Scroll down to the form you want to delete. 
Once is highlighted blue, click your delete key on your keyboard. 
click “remove” to the question. 
To go back to your tax return, simply click the same upper left tab “Easy Step”

 I hope this helps you. If so, please give it a thumbs up. Good luck.