How to create Drop down boxes to reveal full text?

If you want the paragraph to not be visible unless the title is clicked, you can use Accordion Block to achieve this.
#1. First, add an Accordion Block

#2. Next, enter Title and Description

You will see have this

#3. To remove lines on top/bottom, you can use find Accordion ID

then use CSS code like this

#block-yui_3_17_2_1_1725175574269_15595 div.accordion-divider {
    display: none;
}

You will have

and when click it

to make accordion text show full text, use this code to Custom CSS box

div.accordion-item__description {
    max-width: 100% !important;
}