Add search option to wordpress theme

You can place a search box in your wordpress theme by using
<?php get_search_form(); ?>

You can also add

<form role="search" method="get" id="searchform" action="<?php echo home_url( '/' ); ?>">
    <div><label class="screen-reader-text" for="s">Search for:</label>
        <input type="text" value="" name="s" id="s" />
        <input type="submit" id="searchsubmit" value="Search" />
    </div>
</form>

After that change the id,class or style according to your need

How to add TGM Plugin to WordPress Theme

TGM Plugin Activation is a PHP library that allows you to easily require or recommend plugins for your WordPress themes (and plugins). It allows your users to install and even automatically activate plugins in singular or bulk fashion using native WordPress classes, functions and interfaces. You can reference pre-packaged plugins, plugins from the WordPress Plugin Repository or even plugins hosted elsewhere on the internet.

http://tgmpluginactivation.com/