Good flexibility is important for golf. Not only to help improve performance (e.g. bigger backswing to help increase club head speed and driving distance) but also reduce the risk of golf related injuries, aches and pains (e.g. compensatory movements during the swing adding stress to certain parts of the body).
Here’s some simple flexibility exercises for senior golfers that can performed at home or in the gym. These are are a great place to start, especially if you have not done much flexibility and or stretching before for golf.