Cats need to scratch - so a scratching post is important. Also, you can clip her claws so they are not so long and sharp.
There is spray called Bitter Apples that is supposed to put them off scratching. But if she is scratching to get back in the house then perhaps a catflap is the answer. l have had a small square cut out of three internal doors for the cats- this is to stop them scratching up the carpet to get into another room.
As soon as mine come indoors they make a beeline for their scratching posts - lt seems to be quite normal for them to want to scratch. They have a toy mouse stuffed with catnip tied to the post as well.
My problem has been my dogs scratching at doors. They have ruined the paintwork - so l have had the doors rubbed down and repainted - then clear plastic glass fitted over them. Now when they jump at the doors they do not mark.
Never a dull moment with pets - but still l would not want to be without them.