It really depends. Once upon a time, there were clearcut definitions of which side of the family paid for (and generally, by extension, had input on) which parts of the wedding. But usually the old rules don't apply any more, for a million reasons.
For example, when the rules were put in place, usually women didn't work and didn't bring in an income. Men would be more established as, until fairly recently in history (the past 40-50 years or so), the man was often, or usually, at least several years older than his bride, and not uncommonly 10 or more years older. (Today, in the U.S., grooms are still older than brides on average, but only by a couple of years.) So that made a difference in who "could" pay for what.
Also, when the rules were put in place, men and women generally didn't live together first, and were starting with nothing.
Probably most important of all, it was an "exchange" and a way of balancing, supposedly, in a family that might have both boys and girls.
Okay. All that said, today, it is really up to you how involved you want your future MIL to be, and up to her how involved she tries to be. It's tricky and can be a touchy subject. Feelings get hurt, threats get made ("If we can't help you pick out the flowers, we're not paying for them," etc.). So tread carefully. I'm attaching an article just for general reference. It's about who pays for what, but again, those are the things that usually come with the "input" stipulation attached.