On the W-2 form there are boxes 12a,code C, $741.60; 12b, code M, $45.98; 12c, Code N, $10.75. As there are amounts in each one of these boxes, how do enter those?

Yes, you can enter your Box 12 information using TurboTax Deluxe Online edition

Continue your return then

1. Select the TurboTax "Search" box located near the top right of your screen
2. Type "w2" into the search box
3. Pick "Jump to w2" from the results list
4. On the "Here's your W-2 info" screen, "Edit" the W-2 you want to change
5. Scroll down and add the code "C" for Box 12a first and the amount
6. Next, click "Add another row" (see attached image)
7. Now enter the code "M" for Box 12a and the amount
8. Continue adding rows until you have recorded all the entries you need for Box 12

Help with updating your W-2 information is at https://ttlc.intuit.com/questions/1899564-how-do-i-change-my-w-2-info-in-turbotax?jump_to=answer_330...