I want to find out how can I get my bamboo plant to grow taller?

Try feeding it some plant food.

it may also depend on the type of bamboo you have. There are different varieties with variable heights. Also the denser the bamboo becomes the taller it will grow to stretch for the sun. Be very careful what you wish for! Bamboo can become very invasive from one neighbor to another and continue down the line There are many communities and towns that have banned the planting of bamboo, for that very reason.

Wallysrainbow is right. Height depends upon type. Be very careful with bamboo most becomes invasive. The first 2 years it doesn't seem to then look out!

Invasive is putting it mildly. Definitely a "take over" plant. More like overbearing, persistent, intense!! I'm forever cutting mine down . Come get!! You can have as much as you want!! My neighbor had his professional taken down.

Hopefully yours is in a pot, you could fertilize, maybe a bigger pot.