I agree with Jessica. When it is a particle which is used after the subject, it's written は and it's read WA. When it is a part of one word, it's written and read HA.
Ex.) HA: はじめまして(nice to meet you)、はし(chopsticks / bridge)、は(leaf)、はな(flower / nose)
これはさくらのはなです。--> kore wa sakura no hana desu.
わたしははしをつかいます。--> watashi wa hashi wo tsukai masu.
*は after これ and わたし is a particle, so it's pronounced WA.
I hope this was helpful.