app/views/onboarding_mailer/welcome_email.html.erb
<h1 class="mb-3"><%= t('onboarding_mailer.welcome_email.title') %></h1>
<p>
<%= t('onboarding_mailer.welcome_email.paragraph_1') %>
</p>
<div class="s-3"></div>
<p>
<%= t('onboarding_mailer.welcome_email.paragraph_2_html') %>
</p>
<div class="s-3"></div>
<p>
<%= t('onboarding_mailer.welcome_email.paragraph_3') %>
</p>
<%= link_to t('onboarding_mailer.welcome_email.view_your_school'), school_url(@school), class: 'btn btn-primary mt-3 mb-3'%>