We have a leaking window but in the mean while need to repair the interior after removing shutters. I can just spackle and paint but someone said I need to put primer (not paint primer but spackle primer) to keep moisture off of the spackle.

I went to home depot and they couldn't tell me except just spackle, sand, prime and paint.

Any advice on how to fix this the best possible way until the window if fixed from the exterior. What product to use?

Here are the photos.