No, not at all. I have a number of them, and not one is invasive! Is it bracken you're thinking of maybe?

I wish some of my ferns were thugish but they are so well behaved. Certainy bracken is invasive and it is a fern.

I was just thinking of getting some for my garden and just wanted to check first. Thanks

We had Mateuca Strutheropsis (Sp?) Shuttlecock fern for some time. Can't say it was invasive, as such, but it did tend to spread a bit.

How can I tell the difference between fern and bracken ?

Bracken grows a long stem bare at the bottom, which has smaller fern type leaves growing off it. Ferns are generally full of leaflets almost to the bottom of the stem.
this isn't a good botanical way of telling the difference but as a rough guide its pretty useful. If you buy your ferns from a garden centre there will be no danger of your being sold bracken. If you do Google Images the first two pictures are the most helpful - the others may be confusing. Bracken really is invasive and quite hard to get rid of, and it is also rather poisonous, although people used to eat the very new shoots at one time.

I've never seen bracken plants for sale anywhere. I don't think you'd go and dig it up off a moor, would you, Pdb! Anyway, that's illegal.