If you wish to hit a straight golf shots you definitely do not want to flare your left foot toward your target after gripping your club.
Assuming you have locked-in a square alignment and an on line swing path of your club face with the face of your club centered directly behind your ball during your setup routine, and then flare your left foot toward your target, you will open your shoulders to your target line and have difficulty hitting a straight golf shot.
Some golf swing instructions recommend flaring the left foot toward the target during the set up proceedings.
Assuming an otherwise ideal stance, posture and ball placement at final address, all the flaring of the left foot accomplishes is to correspondingly rotate your shoulder line to the inside of your target line to create a recipe for disaster.
You definitely should not expect to hit a golf ball straight if you flare your left foot in this manner after gripping your club and addressing your ball.
What you can expect is to come “over the top” during your down swing and deliver an open club face to your ball at impact on an out-to-in swing path across your target line to produce a slice ball flight.
As you probably are aware a slice golf shot occurs as a result of the clubface contacting the ball at impact with an open alignment on an out-to-in path across the target line.
Since the clubface effectively is aligned openly the instant a conventional golf grip is assumed as well as on an out-to-in swing path to establish a slice ball flight alignment, why compound the problem by flaring the left foot in the direction of the target and increase the degree of a slice golf shot?
A better golf method would be to square the toe line parallel with the target line at final address in order to form a square body line with the target line and avoid an even more pronounced slice golf shot.
If you want to hit straight golf shots, you should refrain from flaring your left foot toward you target after gripping your club and addressing your ball.