If my website in in WP, can i install CiviCRM in drupal?
Welcome! What Masswear says is not right. You can have your website in wordpress and have CiviCRM in a Drupal installation.
You can the connect your wordpress site to civicrm with a plugin called CiviMcRestFace. This plugin creates an api connection to civicrm. So you need an API key (of the civicrm user) and the site key.
When you want to send signup forms to civicrm you can then use Caldera Forms and Integration of CiviCRM Form Processor with Caldera forms. You then also need the Form Processor extension in CiviCRM.
I believe that the Contact Form 7 CiviCRM Integration plugin also works with CiviRestFace. But I am not sure about that what I do know is that it connect to an external CiviCRM
When you want to display data from your drupal CiviCRM installation you can use the wpDataTable plugin and the Data Source CiviCRM api for wpDataTable plugin to display data from a civicrm as a table on your word press pages. Eventually you can use the Data Processor extension in CiviCRM to create custom api's through the user interface.