Thank you for replying and I thought so just wanted to double check as I e never kept platy fish but now I can take the right step to making sure she's OK when releasing the fry hopefully I can save se I don't want to move her as I've read this can stress her out especially when she only just been added to my tank from the pet store there plenty of rock plants and hideaways for them
She'll definitely be happier giving birth in the main tank, especially since she's new and just settling in
To give the babies the best chance at surviving, if you want to save them all, having a big dense mass of plant matter at the surface gives them the best chance of hiding from any adult fish. Newborn fry tend to head for the surface. Elodea, hornwort, water wisteria, guppy grass - any stem plants like that can be just thrown in the tank and left to float, as they absorb the nutrients they need from the water column, not underground roots like some plants. So you can just leave it floating in the tank, and tiny fry will naturally go and hide in there.
If you want to raise the fry for a while in a different tank, or in a breeder net or box, just check the tank often, especially first thing in the morning before putting the tank lights on or sunlight hits the tank, so the adult fish will still be sleeping. Then you can quickly net the fry into the breeder box/net/other tank.
If you choose to raise them in a breeder net or box, let them back out into the main tank once they're three weeks old. They'll be big enough then to be getting cramped in the box, but not be eaten by adults in the main tank.