Just to second what Nick says, adding lots of organic matter like compost to borders is the solution to dealing with clay as it eventually mixes with it or creates a layer of more workable soil above.
If you think of clay you mould, it helps to understand how it works. With water it becomes sludgey and squishy and locks in water. But when it eventually dries, it goes rock solid. Add water again and it eventually goes back to being squishy.
Don’t be put off by clay though, with plenty of organic matter, it can become one of the best soils to grow in!