RecepBilgin it's a bit broad to answer a question like this. If you have more specific examples or market segments maybe someone can share their experience on the subject.
Out of the box Flarum doesn't include many features, but has a no-js view that works well.
There's an SEO extension adding many features including Opengraph tags.
Some people shared their Google performance/rating in other discussions, it can vary a lot depending on your amount of data and which extensions you use.
