A heavier weight will train your nervous system to recruit more neurons to produce higher amounts of force. If you want to absolute build strength in a particular movement, use a weight where you can’t lift more than 4-6 repetitions per set.
The less experience you have, the more you should focus on lifting in the 7-12 rep range, as you are learning proper technique. Over time, you can add more weight to the exercises, slowly working your way down in repetitions.
You do not have to lift really heavy to build muscle, but you should lift heavy enough to induce some level of muscular fatigue in every set. It is best to stick with weights heavy enough where you cannot accomplish more than 7-12 repetitions per set.