Video Effects Application

Any.
iMovie may have some of those as templates. But you cam create those effects with any video application changing colors. Just look at the effect you like in Instagram and create something similar.

It is easy for me because I work with video but with someone with no experience I may be talking Chinese. There may be some apps at the aple store that can have similar effects to apply to your quicktime movies. Just do a search, there has to be.

If you go to YouTube there are course you can learn about a pacific effect you wish to learn. If you are playing around with video at some stage you are going to have to learn. I would leave that word "Complicated" well alone if you are learning editing.