Welcome, enter your question. Please start with words like "Who, What, Where, When, Why, How, etc..."

To use a Vocaloid trial, you have to download and install it. The trials that are currently available:

MEIKO , Hatsune Miku V4x English and Japanese, Hatsune Miku V3 English and Luka V4x Hard have trial versions on Sonicwire, however, they are limited by what they can sing and how long they can sing.

SF-A2 miki, Kaai Yuki, Hiyama Kiyoteru, and Nekomura Iroha have 14-day trial versions available on AH-Soft's website, however if you do not own VOCALOID2 in English VOCALOID2 demo will be in Japanese.

And MAYU has a trial available from her official website.

MAIKA also has a 14-day trial avaliable through her official website.

CUL, Lily, kokone, Gachapoid, Chika, and all of the GUMI Megpoid APPENDS (excluding english), have 14-day demo trials available from the linked sites. However, they are limited to how long they can sing.