Having a well-built chest certainly makes you look good and athletic. The stronger the chest muscles the stronger your upper body.
The chest is made up of two muscles the pectoralis (pecs) major and the pectoralis minor. The pectoralis major is the most superficial muscle. It is large and fan-shaped and has two parts namely the clavicular head (upper) and sternal head (lower). Whereas the pectoralis minor lies beneath the pectoralis major and is a thin, triangular-shaped muscle.

Push ups

A push-up is a common calisthenics exercise performed in a prone position by raising and lowering the body using the arms. Push-ups exercise the pectoral muscles, triceps, and anterior deltoids, with ancillary benefits to the rest of the deltoids, serratus anterior, coracobrachialis and the midsection as a whole.

Barbell bench press

Lie back on a flat bench. Using a medium width grip (a grip that creates a 90-degree angle in the middle of the movement between the forearms and the upper arms), lift the bar from the rack and hold it straight over you with your arms locked. This will be your starting position.
From the starting position, breathe in and begin coming down slowly until the bar touches your middle chest.
After a brief pause, push the bar back to the starting position as you breathe out. Focus on pushing the bar using your chest muscles. Lock your arms and squeeze your chest in the contracted position at the top of the motion, hold for a second and then start coming down slowly again.and repeat it

Incline bench press

This Incline Bench Press is an excellent exercise for building the upper part of the chest, which many people have a problem with. It recruits a lot of the upper muscles, a lot of the shoulder muscles at the same time. It's an excellent exercise to do.

Decline bench press

The first benefit of the decline bench press is that it targets the lower portion of your chest better than the flat bench as well as the incline bench. This is extremely important if you really want your chest to be round, wide, and defined.
Because the angle of your arms is lower relative to your torso than in a standard bench press, the decline bench press primarily targets the lower part of your chest, or pectoral, muscles. The exercise also works your triceps and anterior deltoid muscles.

Chest fly

The chest fly or pectoral fly (abbreviated to pec fly) primarily works the pectoralis major muscles to move the arms horizontally forward.
Lie down on a flat bench with a dumbbell on each hand resting on top of your thighs. The palms of your hand will be facing each other.
Then using your thighs to help raise the dumbbells, lift the dumbbells one at a time so you can hold them in front of you at shoulder width with the palms of your hands facing each other. Raise the dumbbells up like you're pressing them, but stop and hold just before you lock out. This will be your starting position.
With a slight bend on your elbows in order to prevent stress at the biceps tendon, lower your arms out at both sides in a wide arc until you feel a stretch on your chest. Breathe in as you perform this portion of the movement. Tip: Keep in mind that throughout the movement, the arms should remain stationary; the movement should only occur at the shoulder joint.
Return your arms back to the starting position as you squeeze your chest muscles and breathe out. and repeat.