Hello

I'm Tsuyumi. Please call me Tsuyu. I'm a student in the college,and i'm learning English. I want to speak fluently English (English Fluently), because I will go to abroad from Japan next spring. I want to be able talk about many things in English.Please, become my friend. Thank you for reading my sentence.

Hello

I'm Tsuyumi. However, please call me Tsuyu. I'm student in the college and I'm learning English. I want to speak English fluently because I live in Japan and I will go to abroad next spring. I want to be able talk about many thing in English. Please, become my friend. Thank you for reading my sentence.

Using "however" softens the tone of the first sentence. It was correct before so you do not need to use this specific correction. 

Hello

I'm Tsuyumi. Please call me Tsuyu. I'm a student in the college, and I'm learning English. I want to speak fluently in English because I will go to abroad from Japan next spring. I want to be able to talk about many things in English. Please, become my friend. Thank you for reading my sentence.