For zoom lenses that I am going to use mostly at the long end for a particular purpose (eg portraits) I use a longer hood than the general purpose one. With few exceptions, the hood on a zoom is relatively ineffective at the long end. Therefore it may make sense to buy a hood that is more effective at the long end, even though it obscures the field of view at the wide end. It's a personal choice, of course.
You can get screw-in hoods.
You can also get compendium hoods - ie hoods with bellows so you can change the length of them. These usually come with one, two or more filter slots for rectangular filters.
Best,
Helen